Edited by: Anna Gavarró, Autonomous University of Barcelona, Spain
Reviewed by: Rosalind Jean Thornton, Macquarie University, Australia; Maria Garraffa, Heriot-Watt University, UK
*Correspondence: Nadezhda Modyanova
Alexandra Perovic
This article was submitted to Language Sciences, a section of the journal Frontiers in Psychology
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Deficits in the production of verbal inflection (tense marking, or finiteness) are part of the
One key difference between adult and child grammar, according to Wexler (e.g.,
(1) He bite my fingers. (Nina 2;0.0, CHILDES, Pierce,
(2) Her have a big mouth. (Nina 2;2.6, CHILDES, MacWhinney,
At the same time that TD children produce OIs, they demonstrate knowledge of the difference between nonfinite and finite verbs, as well as other important aspects of morphosyntactic structure (see Wexler,
Difficulties with finiteness have been observed in other developmental disorders, most notably in Specific Language Impairment (SLI). Children with SLI are found to be considerably delayed in finiteness relative to both their TD language- and age- matched controls, and this phenomenon was termed the Extended Optional Infinitive (EOI) stage (Rice et al.,
Our paper addresses whether children with ASD show the pattern of morphosyntactic phenomena associated with the OI stage in TD and with the EOI stage in SLI so that we can answer whether children with ASD are in the EOI stage. This topic is particularly interesting in view of the current controversies on whether similarities in linguistic profiles of SLI and ASD are indicative of links between these two populations. Some researchers contend that patterns of linguistic impairments in ASD are reminiscent of those in SLI (e.g., Kjelgaard and Tager-Flusberg,
To establish whether there exists a deficit in finiteness in ASD, similar to that observed in SLI, we carried out an experimental study employing materials used to establish finiteness difficulties in SLI, in a large number of children with ASD of heterogeneous abilities, divided into two groups in line with the classifications in the literature (Kjelgaard and Tager-Flusberg,
Considering how well researched finiteness is in TD and in SLI, and especially the current debates of possible links between SLI and ASD (e.g., Tager-Flusberg,
Early studies focusing on grammatical morphology in spontaneous speech in children with ASD report difficulties with both past and present tense; however, results from these studies, which included small samples of children with autism and with heterogeneous language and cognitive abilities, are far from clear. Bartolucci et al. (
More recent studies used methods more akin to those used in SLI research, such as TEGI-type tasks which employ constrained elicited production of present and past tenses, rather than spontaneous speech. Botting and Conti-Ramsden (
In the only study that divides children with ASD into subgroups according to impaired or unimpaired language, as measured by vocabulary skills, Roberts et al. (
Studies using different methodologies still show subtle differences in the mastery of finiteness in ASD compared to control children. Eigsti and Bennetto (
The only study to show an age appropriate performance by children with ASD is Walenski et al. (
Taken together, these findings demonstrate a wide range of finiteness abilities for children with ASD. A clear trend is that children with ASD show finiteness performance below their chronological age level, just like children with SLI. Compared to TD controls (matched at least on NVIQ for all studies that used them), children with ASD are usually worse on tense marking, but this largely depends on whether ASD participants have higher or lower NVIQ levels.
A major aim of the present study is to compare the production of finiteness in children with ASD to that of TD children functioning at similar nonverbal MA level. This approach allows us to characterize precisely the severity of the deficit in finiteness found in children with ASD relative to TD peers. Furthermore, we aim to infer whether the language system underlying finiteness in ASD is intact, delayed (showing similar patterns as younger matched TD controls), deviant (showing patterns not found in TD at all) or disrupted (showing worse performance than the youngest TD controls, that is a severe delay, suggesting an “asynchrony” in development, as is the case for children with SLI) (Rice,
In our study, the children with ALI have not only a deficit in general language ability but also nonverbal IQ deficits. The question we will want to ask is whether any delay that these children show on finiteness is due solely to their lower IQ and their lower level of general language abilities, or whether it goes beyond these. Our hypotheses are illustrated in (3).
(3) Hypotheses: Children with ALI may show:
Intact behavior on finiteness (equivalent to TD peers of the same age);
Deviance (showing properties that never appear in typical development);
Delayed behavior on finiteness (not deviant, but finiteness rates that are not significantly worse than younger controls who are matched on nonverbal MA and general language abilities);
Disrupted behavior on finiteness (not deviant, but finiteness rates that are significantly worse than younger nonverbal MA- and language-matched controls, cf. Rice,
Each of these four possibilities is a potential hypothesis. Of course, given the literature survey that we have just presented, we do not expect that children with ALI will show profile (3a), an intact pattern. So we can take profiles (3b, c, d) (deviant, delayed, disrupted) as hypotheses to test. We will not select one of these as our only hypothesis here; rather, the goal is to carry out a study that allows us to decide between these.
Although our study does not contain children with SLI, we can compare rates of finiteness with children with SLI from the literature. If our children with ALI show similar rates of finiteness as children with SLI functioning at comparable levels of cognitive and language abilities, this would support the idea that children with ALI have both ASD and SLI. Additionally, if children with ALI show a disrupted pattern of finiteness with respect to TD controls, then children with ALI would be like children with SLI with respect to this piece of language. However, if children with ALI show lower rates of finiteness than children with SLI, we can conclude that development of children with ALI is even more disrupted than that of children with SLI, and that there is more to language impairment in ALI than what is found in SLI. Moreover, children with ALI may potentially show a pattern of deviance that children with SLI do not show.
For children with ALN, grammatical deficits are not expected by definition. However, it is still important to compare knowledge of grammar in children with ALN relative to that of TD children to establish whether indeed children with ALN are “language normal” with respect to finiteness. It is always possible that a deficit in finiteness is not picked up by the standardized tests that establish a child as being ALN. We can thus consider the same hypotheses (3) for ALN.
Our choice of method of constrained elicited production, rather than natural production, is motivated by the following considerations. To determine the rate of finiteness, it is necessary to count not only children's production of relevant morphemes, but also omission thereof in obligatory contexts. Proportion of usage of an obligatory morpheme in obligatory contexts is the central measure that has been used in studies of production data concerning morphology since at least Brown (
As observed in the literature review, one of the challenges in making sense of the data in ASD is the heterogeneity in the verbal and nonverbal abilities in this population. To control for the heterogeneity of our participants' abilities, we follow recent literature and divide our participants into two groups based on their language-related phenotypes: Autism Language Normal (ALN) and Autism Language Impaired (ALI) (e.g., Kjelgaard and Tager-Flusberg,
We focus on comparisons of ALI and ALN groups and their matched TD control groups on finite responses on past and present tenses, as well as a recalculation based on all response types (percent correct vs. bare form vs. other responses), in obligatory contexts. We analyze participants' responses for other morphosyntactic aspects of the OI stage. We further evaluate our participants' finite responses via the criterion scores developed by Rice and Wexler (
To establish the influences of general grammar and vocabulary skills, nonverbal IQ and autistic symptomatology, we calculate correlations between children's finiteness levels and their scores on standardized tests of language, nonverbal reasoning, and measures that are used as a gold standard for diagnosis of ASD in the research literature, ADOS and ADI-R (Autism Diagnostic Observation Schedule: Lord et al.,
One hundred and sixty-four children participated in the study: 83 children with ASD (Chronological Age (CA): 4.35–16.3 years; 11 female)
10.62 (3.07) | 18.42 (8.82) | 74.75 (22.90) | 71.53 (18.72) | 81.32 (30.21) | 67.60 (16.55) | 4.81 (3.69) | 60.05 (7.96) | |
6.42–16.32 | 0–39 | 40–112 | 40–107 | 29–147 | 40–100 | 0–12 | 55–85 | |
6.03 (2.63) | 18.53 (8.39) | 108.41 (11.66) | 88.53 (35.8) | 110.14 (11.64) | 8.91 (5.41) | 104.77 (14.95) | ||
3.5–13.2 | 4–39 | 88–143 | 34–177 | 84–135 | 0–19 | 83–139 | ||
9.52 (3.35) | 27.13 (8.74) | 108.13 (17.77) | 108.82 (15.15) | 124.11 (40.03) | 106.98 (15.81) | 13.41 (4.87) | 97.39 (12.02) | |
4.35–16.25 | 7–43 | 65–151 | 76–145 | 43–192 | 72–133 | 2–20 | 81–132 | |
9.54 (3.87) | 26.91 (9.59) | 108.89 (13.19) | 125.56 (41.49) | 110.27 (15.96) | 14.59 (4.61) | 104.23 (12.80) | ||
3.95–17.11 | 9–44 | 85–142 | 46–188 | 80–147 | 2–20 | 81–137 | ||
ALI-TD < ALI |
ALI < ALN |
ALI < ALI-TD |
ALI < ALN |
ALI < ALN |
ALI < ALI-TD |
ALI < ALI-TD |
ALI < ALI-TD |
This study was approved by the Committee on the Use of Humans as Experimental Subjects at the Massachusetts Institute of Technology. Written parental consent was obtained for all participants.
Fifty-eight participants with ASD were recruited with the help of the Division of Developmental Medicine, Boston Children's Hospital (BCH), Harvard Medical School, for the Simons Simplex Collection of the phenotypic and genetic factors in ASD (Lord et al.,
In part following Perovic et al. (
(4) We classified children as ALN if they scored at or above the 10th percentile (i.e., a standard score (SS) of 81 or above) in TROG-2 and in at least one of the two vocabulary tests (KBIT-Vocabulary and PPVT-3). 96% of ALN participants were at or above the 10th percentile on all three tests.
(5) Children were classified as ALI if their score was below the 10th percentile in TROG-2, and below the 10th percentile in at least one of the two vocabulary tests. This was true for 84% of ALI participants. Five participants who had good scores on both vocabulary tests, but with TROG-2 scores in the impaired range (SS of 69 or below), were also assigned to the ALI group. Finally, one participant who scored below the 10th percentile on both vocabulary tests, but had SS of 85 on TROG-2, joined the ALI group
TD controls were recruited from Boston and Cambridge, Massachusetts area daycares and afterschool programs, and had no known cognitive or language delays or hearing impairments. They were individually matched to ASD participants on the raw score of KBIT Matrices, forming two groups: TD controls of ALI group (ALI-TD,
Table
The groups were not gender-matched due to a limited sample size of TD controls. To control for effects of gender, we included this variable as a covariate in our subsequent analyses: no significant effect of gender was found.
Finally, because not all children with ASD had ADOS and ADI-R scores, we did not match the ALI and ALN groups on these measures. It is notable that for the subgroups of ALN (
Three picture probes of the Test of Early Grammatical Impairment (TEGI, Rice and Wexler,
The phonological probe determined whether children could pronounce the consonant sounds relevant to present and past tense inflections, /
The present tense probe assessed whether children could produce third person singular inflection using a representative picture for a profession and the following prompt: “This is a teacher. Tell me what a teacher does.” If participants replied with a plural subject, e.g., “Teachers teach” or without a subject, e.g., “Teach,” they were reprompted to provide an answer with a singular subject. Following the manual, we used such phrases as “Say a whole sentence,” or “Start with he or she.” If that did not work, the experimenter started the sentence for the participant, saying, e.g., “A teacher…” after which the participant sometimes completed the sentence. Finally, if a child produced an answer which was semantically appropriate but was neither finite nor nonfinite, e.g., a progressive form, the experimenter agreed with the participant, and then prompted him or her with, “Tell me what else a teacher does?” Often, especially with lower functioning or younger participants, these prompts did not produce the desired kind of response, and we simply recorded whatever answers the participants provided. There was one training example and 10 trials.
The past tense probe assessed whether children could produce the -
Answers were scored following the instructions in the TEGI Manual (Rice and Wexler,
“Unscorable” answers, ones that we did not purposefully elicit, were those without verbs (nouns only), inappropriate tenses for the prompt, and responses with “does,” “did” or “done.” Repeated use of “he/she finished” was also marked unscorable (c.f. Rice and Wexler,
The distribution by all response types, that is percentage of correct forms vs. bare forms vs. unscorable or unattempted answers, was also analyzed separately, following Roberts et al. (
Unscorable answers were analyzed separately for those participants that produced them for any tense or other errors. All answers were analyzed for other aspects of morphosyntax, namely subject-verb agreement and case.
We also counted whether there was an overt or a null subject with an inflected or nonfinite (bare) verb. Because the only appropriate answers to our elicitation task contain third person singular subjects and verbs (and also because when the children
A few participants from the ALI group did not produce any scorable responses for certain tenses, and were thus excluded from analyses for that tense: two were excluded from analyses for present tense (
For one third of ALI-TD and about half of ALN-TD participants, detailed scores of the probes were not available, just the rates of finiteness for present and all past tenses in percent (included in Table
65.30 (35.67) | 67.83 (33.6) | n.s. | |
90.53 (21.64) | 92.43 (18.41) | n.s. | |
87.80 (26.06) | 92.82 (18.39) | n.s. | |
98.76 (6.15) | 96.92 (12.10) | n.s. | |
ALI < ALI-TD |
ALI < ALI-TD |
70.85 (35.61) | 72.54 (30.90) | 47.54 (32.22) | 25.00 (28.69) | n.s. | |
95.80 (10.25) | 91.19 (17.41) | 61.97 (29.50) | 29.21 (21.79) | n.s. | |
92.79 (20.40) | 92.19 (19.35) | 71.50 (32.82) | 20.69 (24.54) | n.s. | |
93.96 (17.13) | 95.95 (15.78) | 82.87 (26.16) | 13.08 (18.90) | n.s. | |
ALI < ALI-TD |
ALI < ALI-TD |
ALI < ALN |
n.s. |
53.10 (38.91), 193 | 19.68 (21.93), 72 | 22.22 (25.98), 80 | 5.00 (19.78), 18 | |
90.39 (19.90), 235 | 7.31 (15.64), 19 | 2.31 (9.92), 6 | 0 (0), 0 | |
85.94 (26.80), 385 | 10.75 (21.66), 49 | 3.31 (6.38), 17 | 0 (0), 0 | |
97.08 (9.99), 233 | 1.67 (8.17), 4 | 1.25 (6.12), 3 | 0 (0), 0 | |
ALI < ALI-TD |
ALI > ALN-TD |
ALI > ALI-TD |
n.s. |
All ALN and ALN-TD participants passed all 4 subtests of the phonological probe. One ALI participant did not pass one of the four subtests of the probe, the /
The participants' mean rates of finiteness, that is the mean of individual finite responses divided by the individual's sum of finite and nonfinite (bare) responses, are illustrated in Table
Table
We find a significant effect of group for regular past tense finite responses
We reanalyzed our data by percent of all response types, so that the denominator includes all verbs in the probe, not just those responses that are scorable. Sums of raw numbers are also indicated in Tables
There was significant effect of group for most response types in most tenses. There was no significant effect of gender. Pairwise comparisons (Bonferroni corrected) indicated that the ALI group performed worse than other groups on percent correct, and had more percent bare, percent unscorable and percent unattempted (no response) responses.
For present tense (Table
For regular past tense (Table
57.39 (37.64), 208 | 15.06 (17.55), 55 | 16.74 (22.12), 61 | 10.81 (26.55), 39 | |
92.34 (16.32), 241 | 4.20 (10.25), 11 | 3.46 (13.84), 9 | 0 (0), 0 | |
92.57 (20.37), 418 | 7.21 (20.40), 33 | 0.22 (1.49), 1 | 0 (0), 0 | |
92.92 (18.05), 223 | 5.83 (16.92), 14 | 1.25 (4.48), 3 | 0 (0), 0 | |
ALI < ALI-TD |
n.s. | ALI > ALI-TD |
ALI > ALI-TD |
For irregular past tense (Table
55.18 (38.28), 161 | 37.34 (32.68), 109 | 17.84 (23.84), 52 | 14.07 (16.60), 40 | 18.25 (26.90), 52 | 12.5 (31.05), 36 | |
89.42 (20.52), 185 | 61.33 (29.58), 127 | 28.09 (22.00), 58 | 7.21 (13.31), 15 | 3.37 (13.02), 7 | 0 (0), 0 | |
91.11 (20.61), 327 | 70.98 (33.08), 255 | 20.13 (24.15), 72 | 6.87 (16.39), 24 | 1.75 (5.44), 6 | 0.28 (1.86), 1 | |
94.91 (16.31), 183 | 82.18 (26.82), 158 | 12.73 (18.59), 25 | 4.05 (15.78), 8 | 1.04 (5.10), 2 | 0 (0), 0 | |
ALI < ALI-TD |
ALI < ALI-TD |
n.s. | n.s. | ALI > ALI-TD |
ALI > ALI-TD |
In the ALI group, there was a total of 193 “unscorable” answers for 26 participants, a rate of 19.0% given 1,015 total responses across tenses and participants.
The ALN group had just 24 unscorable responses in 16 participants, a rate of 1.9% given 1,261 total responses across tenses and participants.
Table
Simple past (finite) | 2 (2) | 369 (35) | 0 | 745 (44) |
Simple present (finite) | 193 (29) | 8 (4) | 385 (43) | 0 |
Bare stem (nonfinite) | 72 (22) | 95 (25) | 49 (13) | 57 (9) |
Present progressive (present tense auxiliary + progressive participle) | 24 (11) | 21 (8) | 3 (3) | 0 |
Past progressive | 0 | 1 | 0 | 0 |
Progressive participle |
21 (9) | 35 (9) | 3 (2) | 2 (2) |
Present tense auxiliary with bare verb (omission of |
2 (2) | 1 | 0 | 0 |
Copula “is” | 5 (2) | 0 | 0 | 0 |
Future “is going to” | 2 (1) | 1 | 0 | 0 |
“s/he is (all) done” | 0 | 10 | 0 | 2 (2) |
“Does” | 3 (3) | 0 | 2 (2) | 0 |
Modal | 1 | 0 | 0 | 0 |
“Finished” | 0 | 13 (4) | 0 | 0 |
“Did” | 0 | 8 (5) | 0 | 0 |
Nouns for subject | 7 (3) | 2 (2) | 0 | 0 |
Nouns for object | 19 (7) | 6 (3) | 1 | 0 |
Preposition phrases | 7 (6) | 0 | 0 | 0 |
Adjectives | 3 (2) | 0 | 0 | 0 |
No response | 18 (3) | 75 (7) | 0 | 1 |
Unscorable due to experimenter issues e.g., responses were unintelligible or there was disagreement between scorers | 17 (10) | 11 (9) |
Overall, the ALI participants were hardly ever confused between the simple past and simple present tenses, giving a total of 10 errors out of 572 uses of simple tenses for all participants for all probes, a rate of 1.7%.
In the present tense probe, the progressive participle -
In the past tense probe, present tenses were used 40 times, 6% of the 652 total responses for that probe. The majority of these (21) were in present progressive tense, with 2 participants contributing 14 of these. These two participants produced proper past tense morphology only four times between them. Other present tense responses included simple present, present tense auxiliary with bare verb, and “s/he is (all) done.”
A present participle (stem +
In the past tense probe, there was one case of simple present tense together with past tense overregularization, “catchesed.” Finally, there was one future tense that is interpreted as future/intention, “she's gonna run” for the picture with a girl tying her shoelaces.
Across the probes, there were three instances (one each from three ALI participants) using the auxiliary “is” and a bare form of a verb, omitting -
Nobody in the ALN group misused past tense in the present tense probe and vice versa, that is 0 out of 1,130 simple tense responses for all ALN participants in all probes. In addition to those responses detailed in Table
The responses of participants with ALI and ALN were also examined to establish the presence of any difficulties with morphosyntax, specifically with case marking and subject-verb agreement. We found no such errors: for example, no participant used a first or second person pronoun with third person singular verbal inflection in present tense, and none misused case on pronouns.
There were only three instances of first person pronoun in nominative case for the subject, and only two in accusative case for the object. The second person pronoun “you” was used for a subject by only one person in two complex sentences. “You” was regularly used for objects, especially with a picture of a dad or a nurse, “…helps you,” a total of 11 times for 8 ASD participants. The determiner “your” was used primarily with a picture of a dentist, e.g., “(…) clean(s) your teeth,” a total of 19 times for 18 ALI/ALN participants.
All pronouns that were used were in appropriate cases for their sentence role, with nominative for subjects, accusative for objects, possessive/genitive in relevant constructions.
For third person singular present tense, pronouns “he” or “she” or “it” were 100% correctly used, as the subject by 17 ALI participants: 49 times with finite verbs and 10 times with nonfinite verbs; and by 11 ALN participants: 46 times with finite verbs and 3 times with nonfinite verbs. Noun phrases were used as the subject by 10 ALN participants: 56 times for finite and 3 times for nonfinite verbs; and by 9 ALI participants: 33 times for finite verbs and 8 times for nonfinite verbs. There were no instances of incorrect use.
Because the probes focused on the elicitation of singular subjects, plural subjects were not purposefully elicited. Children with ASD did not make any agreement errors here, with the two overt plural subjects that two participants in the ALN group produced showing correct agreement. One plural subject in the ALI group was also appropriate.
The presence of null or overt subjects was calculated in 70% of ALI participants (
We begin by comparing null vs. overt subjects within and between groups (collapsing across non/finite verbs) (Table
53.44% (101/189) | 46.56% (88/189) | n.s. | 73.49% (219/298) | 26.51% (79/298) | ||
64.67% (108/167) | 35.33% (59/167) | n.s. | 78.25% (223/285) | 21.75% (62/285) | ||
n.s. | n.s. | n.s. | n.s. |
Table
83 | 18 | 177 | 42 | |
50 | 38 | 47 | 32 | |
37.59% | 67.86% | 20.98% | 43.24% | |
Ratio | 1.8 | 2.1 | ||
102 | 6 | 221 | 2 | |
43 | 16 | 35 | 27 | |
29.66% | 72.73% | 13.67% | 93.10% | |
Ratio | 2.5 | 6.8 |
Chi-square tests for independence were used to examine the relationship between null/overt subjects and non/finite verbs within each group. We find significant relationships in the ALI group for present tense,
Pearson Bivariate Correlations
In the case of the ALI group, we find significant correlations for different aspects of tense with receptive and productive vocabulary, receptive grammar, as well as NVIQ, but not with CA (Table
0.329 | 0.179 | 0.322 | 0.538 |
0.399 |
|
0.152 | 0.265 | 0.352 |
0.555 |
0.352 |
|
0.293 | 0.243 | 0.370 |
0.328 | −0.005 | |
−0.102 | 0.101 | −0.145 | 0.14 | 0.316 | |
0.211 | 0.348 |
0.251 | 0.472 |
0.288 | |
0.24 | 0.410 |
0.464 |
0.645 |
0.388 |
|
0.293 | 0.339 |
0.431 |
0.618 |
0.411 |
In the ALN group, on the other hand, finiteness strongly correlates with CA only (Table
0.420 |
−0.037 | −0.107 | −0.004 | −0.075 | |
0.376 |
0.152 | 0.075 | 0.221 | 0.357 |
|
0.735 |
0.14 | −0.063 | 0.279 | 0.041 | |
−0.639 |
−0.082 | 0.019 | −0.269 | −0.036 | |
0.436 |
0.145 | −0.13 | 0.132 | 0.024 | |
0.424 |
0.159 | 0.018 | 0.213 | 0.273 | |
0.455 |
0.054 | −0.06 | 0.092 | 0.075 |
In the ALI group, there were significant negative correlations between knowledge of finiteness, including composite tense, and ADI-R scores on the Current Algorithm on domains of Social Interaction, Verbal and Nonverbal Communication, and Behavior (Table
−0.737 |
−0.796 |
−0.862 |
−0.597 |
|
−0.605 |
−0.582 |
−0.614 |
−0.349 | |
−0.231 | −0.199 | −0.337 | −0.278 | |
−0.590 |
−0.551 |
−0.433 | −0.351 | |
−0.767 |
−0.701 |
−0.666 |
−0.597 |
|
−0.678 |
−0.615 |
−0.697 |
−0.45 | |
−0.704 |
−0.700 |
−0.787 |
−0.552 |
−0.269 | −0.332 | 0.107 | −0.144 | |
−0.314 | −0.472 |
−0.078 | −0.466 |
|
−0.32 | −0.188 | 0.51 | 0.377 | |
−0.237 | −0.053 | −0.499 | −0.305 | |
−0.549 |
−0.244 | −0.082 | 0.116 | |
−0.359 | −0.434 | −0.009 | −0.335 | |
−0.291 | −0.375 | −0.056 | −0.278 |
For the ALN group, there were no significant correlations between ADOS and ADI-R scores and composite tense. Only two other measures of tenses had significant correlations. Correct form of irregular past tense [
While the ALI group is clearly impaired on finiteness, the ALN group was not significantly worse than its controls. Analysis of the TEGI criterion score indicates whether there are any absolute delays in finiteness, by comparing the score of each participant to the cut-off score for that participant's age. Performing at or above criterion score is considered age appropriate. Separate ANOVAs were performed for each criterion: for present tense, for all past tense, and for composite tense including all past and present tenses (Table
38.2 | 61.8 | 36.1 | 63.9 | 21.6 | 78.4 | |
80.6 | 19.4 | 91.7 | 8.3 | 83.3 | 16.7 | |
80.4 | 19.6 | 82.6 | 17.4 | 76.1 | 23.9 | |
97.8 | 2.2 | 95.6 | 4.4 | 97.8 | 2.2 | |
ALI < ALI-TD |
ALI < ALI-TD |
ALI < ALI-TD |
There was a significant effect of group for the present tense criterion
Our investigation of finiteness in ASD, the largest to date to include subgroups of children with ASD classified with regard to the presence or absence of language impairment, has revealed two main results (6).
(6) Main Results:
Tense/finiteness is severely deficient in children with ALI;
Tense/finiteness is not compromised in children with ALN.
For the first time in the literature, we observe that the children with ALI perform significantly lower than both age-matched children with ALN, and much younger TD controls matched on verbal- and nonverbal MA, on all tenses: present, and past regular and irregular. Our youngest control group, the ALI-TD (mean age 6.0 years), shows a 91/92% rate correct (present/past). The ALI group (mean age of 10.6 years) shows a finiteness rate of only 65/68% (present/past). This is not just poor performance, but what one would expect from a very young TD child, at a completely different age level. Furthermore, relative to the composite tense criterion cut off point, only 22% of participants with ALI perform at or above their chronological age cut-off for finiteness vs. 83% of their TD controls. As such, the ALI group's performance is showing a severely delayed finiteness system, which can be called disrupted according to the definition in (3d).
In contrast, our children with ALN performed no differently from their TD controls matched on age, nonverbal and verbal-MA, and grammar: the ALN group (mean age 9.5 years) has an 88/93% finiteness rate which is somewhat (though not significantly) lower than ALN-TD group of the same age (99/97%). As such, the ALN group can be said to have intact finiteness knowledge. However, the criterion analysis for composite tense indicates that only 76% of children with ALN perform at or above their chronological age cut-off for finiteness, which is approaching significant difference from the ALN-TD control group (98%). About 24% of the ALN group does not reach the level of finiteness knowledge indicated by the criterion for their age, showing heterogeneity and variability in the ALN group compared to the TD control group (this will be discussed later in section on Insights from Correlations Analyses).
Our findings on ALN are in line with those reported in Eigsti and Bennetto (
In short, children with ALN show age-related heterogeneity, but not a systematic deficit in their finiteness scores, while children with ALI show a severely delayed [“disrupted” in the sense that we introduced in (3d) following Rice,
In the following sections, we discuss our results in more detail and consider their contribution to our understanding of language impairment in autism, and the phenomenon of the OI stage observed in TD, ASD, and in SLI.
An important question, if the study of language in ASD is to be connected to the more general field of language development, is whether children, who show these problems with finiteness, just have some kind of general linguistic deficit, concerning all of language, or whether they are showing the kind of developmental stages that TD children go through. In this paper, we have some of the means to pursue this question with respect to finiteness.
The natural question to ask is, are our participants with autism in the OI stage, a well-known stage that TD English-speaking children grow out of about the age of 4? The stage is sometimes misunderstood to indicate only that the child's grammar allows large amounts of nonfiniteness where finiteness is instead required in the language. As we have seen, this tendency is very strongly observed in our ALI group, and at a very late age. However, the definition of the OI stage (Wexler,
(7) Competence required for the OI stage in English:
Not having a large amount of omission of non-tense morphemes, specifically knowing enough about aspect and its relation to tense, that a tensed auxiliary followed by a verb requires the verb to be a participle;
Knowing the semantic interpretation of the tense morphemes;
Knowing the properties of subject-verb agreement.
First, the OI stage is
Children with ALI sometimes used a present or past progressive tense form. This is inappropriate contextually, as we will discuss later in the section on Children with ALI: Inappropriate Response Patterns. These responses, however, allow us to make certain observations.
First, children with ALI produced 48 instances of a finite form of
Secondly, sometimes the present participle appears
A hallmark of the OI stage is that, although TD children often use a nonfinite form instead of the required tensed form of the verb, they, nevertheless, know the semantic interpretation of the tense morphemes. They do not use a present tense form for past tense or vice-versa (established experimentally for TD children in the OI stage by Schütze and Wexler,
In the OI stage, the basic process of subject-verb agreement is known. Although children often omit a tense/agreement marker in English (in particular here, -
Our probes were not specifically set up to test agreement and case, being purposely designed to elicit third person singular subjects and verbs. However, as our results revealed above, we can in general conclude that there were no errors that showed any problems with agreement or case. For example, of the 3 instances of subject
Children in the ALI group produced a number of responses that were wrong in the sense that they did not answer the elicitation question. The most frequent response of this type was the use of a noun as a response (34 instances in both present and past tense probes). It is possible that these errors are due to difficulties in attending to the task: Roberts et al. (
The second type of inappropriate response was the use of present progressive participles (with or without auxiliaries) for both the present tense probe (45 instances, 12.4% of total responses) and the past tense probe (57 instances, 8.7% of total responses). The contextual conditions that necessitate the present and past tense responses are somewhat different. In the present tense probe, the lead-in question used a generic with third person and a profession title, “This is a teacher,” followed by the prompt, “Tell me what a teacher does.” This should elicit a generic response, “A teacher teaches.” However, the child uses a progressive form. It is possible that some children with ALI have difficulties understanding the concept of generic/habitual. Further research will have to determine whether this is true. Roberts et al. (
In the past tense probe, children with ALI provided 21 instances of the
In order to argue for deviance in children with ALI with respect to morphosyntax, as in (3b), we would have to find evidence that young TD children do not produce inappropriate responses in an elicitation context, unlike children with ALI. In fact, in case of the use of present progressive tense in contexts eliciting simple present tense, very young TD children (ages 2;5–3;4, mean age 2;11) do make such errors at a rate of 3.6% (Thornton and Rombough,
Does this suggest that ALI group's inappropriate responses are not deviant? In order to answer this, we have to consider the context of elicitation in Thornton and Rombough's (
In Thornton and Rombough (
In order to pragmatically justify an answer like “It's not working,” one needs to do only a tiny bit of accommodation; the child has already accommodated by using
In summary, the above discussion of the relevant OI properties in responses of children with ALI points to an extremely delayed OI stage, in fact “disrupted” in the sense we introduced earlier (see 3d). This is supported not only by their pattern of errors (the nontensed verbs where tensed ones are required, including omissions of auxiliary
Our results suggest that finiteness is not a serious problem for children with ALN. Their rates of finiteness are significantly higher than for the children with ALI, and not significantly different from the rates for ALN-TD controls. This lack of a serious deficit in finiteness indicates that the children with ALN are not in the OI stage at their chronological age.
Given that rates of finiteness are so high in the ALN group, we would not expect errors that are characteristic of the OI stage. For reasons of completeness, we note that the ALN group made no errors of interpretation on past and present tense, never omitted
We conclude that the ALN group is not in the Extended OI stage and has the grammatical capacity that goes beyond that stage, on par with their ALN-TD controls. The ALN group's competent performance on our finiteness tasks indicates no overlap with SLI whatsoever. A future study should investigate finiteness in very young children with ALN, who would be expected to be in the OI stage in virtue of their young age.
A well-known phenomenon in TD children (Hyams,
First, there is a much larger tendency to omit the subject if the child produces a nonfinite (untensed) verb. Wexler (e.g., Wexler,
Second, in young TD children there are still many instances of null-subjects of finite verbs, a result that cannot be explained by resorting to grammatical possibilities when the verb is nonfinite. We will discuss why this possibility exists after discussing the results concerning null-subjects in ASD.
As Table
Let us go into more detail starting with the ALI group. Table
Moreover, the pattern provides evidence concerning the possibility that the children with ALI are omitting subjects because they have memory limitations: it may be difficult for children to produce a long sentence that includes a subject. This is an old idea in non-grammatical approaches to child null-subjects that are not grammatical in the adult language. Suppose, as e.g., Bloom (
The children with ALN also produce particularly large rates of null-subjects with nonfinite verbs, reaching 93% for past tense and 73% for present tense probes. Possibly these large proportions are a consequence of the grammatical possibility of null-subjects with nonfinite verbs (there are relatively few of these for the ALN group, as we have seen).
It is also possible that some of these responses are due to the possibility of potential, almost grammatical, replies in our experiment. The past tense probe showed a picture in which e.g., a girl is skating, then one in which the action was completed, and the child was told, “Here she is done. Tell me what she did.” One can imagine an almost grammatical answer, “skate.” One possibility is that the answer is a reduced form of “What she did was skate,” with everything but
In case of the present tense probe, the elicitation says e.g., “This is a teacher. Tell me what a teacher does.” It also seems possible that there is a potential response like, “What a teacher does is teach,” reduced to
We also have to allow for the possibility that the greater proportion of null-subjects is due to the fact that our elicitation provided a strong common ground (topic) and a question about what the common ground
We are left with the issue of null-subjects of tensed verbs, a much-discussed issue in TD. We will adopt the model in Wexler (
The null-subjects of finite verbs in both the ALI and ALN groups may follow from this lack of knowledge of information structure. It might very well be that the kind of defining issues for ASD, e.g., issues related to Theory of Mind, may be enough to cause the relevant difficulties with information structure (which is an interface module, relating syntax to pragmatic/discourse conditions) in both the ALI and ALN groups although their ages would not be consistent with this difficulty in TD. The null-subjects of finite verbs at this late age (~9–10 years) may very well be a sign of autism, whether grammatically impaired (ALI) or grammatically not impaired (ALN). The model of autism that we are working with, and the model of null-subjects and grammatical development more generally that we are working with, predict this particular difficulty for both groups of children with ASD. Further research could be directed toward investigating the consequences of these considerations and toward a more focused attempt to study null-subjects with finite verbs.
To compare, 4-year-olds with SLI, who used 33% nonfinite verbs in their spontaneous production, only showed 16% null subjects with nonfinite verbs, and 2% null subjects with finite verbs; TD children aged 4 and higher showed no null subjects (Schaeffer et al.,
To recap, the fact that both ASD groups differentiate between null-subjects-with-finite-verbs and null-subject-with-nonfinite-verbs suggests, once again, that children with ASD are not simply omitting surface morphemes or words, but are actually producing different linguistic derivations for nonfinite vs. finite verbs, showing a somewhat functioning language system. On one explanation, children with ASD seem to be exhibiting more difficulties with the knowledge of information structure, in particular with the determination of whether or not subjects and predicates are discourse-old.
What other factors, linguistic and non-linguistic, influence the acquisition of finiteness? What can we discover about the relationship of grammar and other cognitive abilities by focusing on the acquisition of different aspects of finiteness by typically and atypically developing populations?
According to Wexler (
Our correlations analyses provide evidence that the ALI group does not have a language system that functions akin to that of the TD children and the children with SLI of Rice et al. (
In the ALN group, on the other hand, finiteness strongly correlates with chronological age only, and, as in TD and SLI children from Rice et al. (
The finding of a lack of correlation for the ALI group between a child's age and composite tense score is striking, but should be taken with some caution. Perhaps some other variable affected whether a child with ALI gets into the study, a variable that correlates with age. A longitudinal study, in the manner of Rice et al. (
Before discussing our results in this section, it is necessary to look into the similarities and the differences between ADOS and ADI-R tests, which are complementary measures of the ASD symptomatology.
ADI-R is a structured interview of a parent or a caregiver, with questions focusing on a child's current behaviors (Current Algorithm) as well as behaviors observed at the most abnormal stage of the child's development so far, usually 4–5 years old (Diagnostic Algorithm). ADI-R assesses abnormalities in the domains of social interaction, communication, and behavior. The measure notes whether a child is verbally fluent (able to produce phrases of three or more words).
ADOS is a structured series of activities and interactions between an evaluator and a child, providing a snapshot of the child's behavior at the time of testing. ADOS measures a similar range of social and communicative behaviors to ADI-R. The test has different modules depending on whether a child is verbally fluent (sentences with multiple clauses) or not (just three-word phrases).
Neither ADOS nor ADI-R directly addresses any specific grammar skills.
Our correlations between finiteness rates and scores from ADOS and ADI-R measures indicate distinct profiles for ALN and ALI groups. In children with ALI, finiteness, especially composite tense, is strongly associated with scores from all ADI-R Current Algorithm domains. Correlations with ADOS measures were less robust, and nonexistent for composite tense. Furthermore, there were no correlations of tense with any of the ADI-R Diagnostic Algorithm scores. The latter observation suggests that estimation of early dis/abilities does not correlate with finiteness dis/abilities at a later age.
The ALN group, on the other hand, showed only a few associations with ADOS Communication and with ADI-R Diagnostic Algorithm Social Interaction scores. Composite tense did not associate with any of the tests for ASD. These findings are in part comparable to Lindgren et al. (
If ADOS and ADI-R are largely measuring the same aspects of ASD symptomatology, why do we find these differences in correlations in ALI? Lack of correlations with ADOS could be explained by the fact that we tested our participants on average a year after they were tested on ADOS and ADI-R. This explanation, however, cannot account for our correlations of the ADI-R Current Algorithm scores and finiteness, which ought to show the same differences in behavior with time. Therefore, an explanation may stem from the differences between ADOS and ADI-R measures. Could it be that parental observations of current daily behavior are in some sense more relevant to the knowledge of finiteness than a clinical interactive observation that lasts an hour or so? It is unlikely that parents estimate their children's verbal fluency by awareness of whether their children produce non/finite verbs. Rather, it may be possible that finiteness is a precursor to overall fluency which parents are sensitive to.
Putting our correlations results together, it seems that in children with ALI, their low overall verbal and nonverbal IQ and their receptive language abilities, as well as the severity of their current symptoms of autism, correlate strongly with their rates of finiteness, which is very different from what we observe in our ALN sample, and in children with SLI and their TD controls studied by Rice et al. (
Here, we compare our results on finiteness in our children with ALI with those of children with SLI and younger TD children from Rice et al. (
In terms of performance on rates of finiteness, our ALI group (aged 10.6) is much better than SLI-5 (twice as high, in fact). Our ALI group is most comparable to Rice et al.'s participants with SLI at ages 6.0 or 6.5, and is lower than their TD group at age 3.5 (but better than the 3-year-olds from the same study). In our participants, there are much greater standard deviations, suggesting a greater variability in ASD than in SLI.
Although children with ALI and SLI may show some similar levels of finiteness, albeit at different ages and levels of general language and cognitive abilities, the overall differences between groups are very great, and thus we hesitate to state that there are similarities between ASD and SLI. Furthermore, we described some kinds of errors that the children with ALI make that the children with SLI are not known to make (see the section Children with ALI: Inappropriate Response Patterns). The children with SLI are in an extended OI stage, showing the same morphosyntactic deficits and competencies as found in young TD children; the children with ALI cannot be said to be in a pure extended OI stage because they show evidence for some patterns that are not found in the OI stage.
Furthermore, there is a conceptual unclarity in what is meant by the formula: ALI = ASD + SLI. Since all researchers are ultimately interested in the etiology (including genetics) of these syndromes, the simplest assumption would be that the syndrome ASD (having no grammatical deficit by itself) is sometimes independently inherited with the syndrome SLI. Such a proposal makes grammatical deficits simply not intrinsic in any way to ASD, with grammatical language impairment in ASD being inherited by chance. Let us call this the
Given that the rate of SLI in children is about 7% (Tomblin et al.,
It is likely that the disorder of ALI (unlike high-functioning autism or ALN) itself causes a range of deficits in the development of different aspects of language, just as other disorders, such as Down syndrome (DS) and Williams syndrome (WS), do. There are examples in the literature for such aspects of complex language as binding dependencies (Perovic et al.,
Our extensive study of finiteness and morphosyntax in two large groups of children with autism and their matched TD controls shows different morphosyntactic abilities relative to the presence or absence of a general language impairment.
Our ALI group shows extensive deficits with finiteness, which are not only large quantitatively, but are also not construction specific, appearing in simple present and past tenses, as well as with auxiliary omission. These difficulties in children with ALI, along with their morphosyntactic competence, are similar to what is observed in very young TD children (much younger than the ALI-TD controls in our study) and indicate disrupted development. The maturational mechanisms underlying the knowledge of finiteness, however, are likely different between those with ALI and those with TD or SLI: autistic symptomatology and overall cognitive and language abilities strongly correlate with finiteness in ALI whereas age does not, indicating a deviant development. Further evidence of deviance comes from the ALI group's use of progressive in habitual/generic contexts. All this suggests that our ALI group is both deviant and disrupted in its knowledge of tense marking. The children with ALI may show some properties, both deficits and competencies, of the OI stage, but they have patterns that go beyond the observed TD or SLI profiles.
On the other hand, there is somewhat slower development of finiteness in children with ALN than their chronological age warrants, but it is still comparable to their TD controls. Furthermore, their knowledge shows evidence of a maturational language learning mechanism, not influenced by autistic symptomatology. However, information structure in ALN shows some deficits, similar to very young TD children and the impaired ALI group. This is striking because information structure deficits should be expected to apply to ASD in general, given the nature of ASD (especially difficulties with pragmatics). Thus children with ALN have pragmatic (in particular information structure, which depends on discourse) difficulties, but not grammatical difficulties, in contrast to children with ALI, who have disrupted tense-marking capacities (in addition to the difficulties with information structure).
It is possible that in all children, the same genetically coded language learning mechanism, called “Universal Grammar” by linguists, is present, and that gives us the ASD and SLI performance consistent with the OI stage of TD children. The genetic deficits of neurodevelopmental disorders then work to limit different aspects of language acquisition, whether grammar or information structure, differently depending on the disorder and its severity.
Following an original suggestion by Wexler (
In autism, finiteness has not yet been used as a biomarker. It is possible that deficits in finiteness can not only assist in distinguishing children with morphosyntactic language impairments or delays within autism subgroups, but also guide genetic studies of language. For example, some genes that are regulated by
Future studies may address other specific markers associated with Tense, and they should also address other aspects of language that are argued to be deficient in children due to the same computational mechanism that limits finiteness. In particular, the Unique Checking Constraint theory of the OI stage predicts that in some (but not all) languages, clitic pronouns should be omitted (Wexler,
KW and AP conceived the study. AP and NM contributed substantially to data collection. NM contributed substantially to transcribing, analyzing and interpreting the data as well as writing the initial draft of the manuscript, with all authors doing some of the writing of some sections. All authors contributed substantially to editing the final versions of the manuscript. All authors have agreed to be accountable for the content of the manuscript.
NM was supported in part by the Singleton Fellows Graduate Fellowship from the Department of Brain and Cognitive Sciences at the Massachusetts Institute of Technology (MIT), and the Simons Postdoctoral Fellowship from the Simons Initiative on Autism and the Brain at MIT. AP was supported by the Brain Development and Disorders Project (BDDP) Postdoctoral Award from MIT. This research was also supported by the Anne and Paul Marcus Family Foundation, and the Brain Infrastructure Grant Program to the Department of Brain and Cognitive Sciences, MIT, from the Simons Initiative on Autism.
KW is a co-author on the Test for Early Grammatical Impairment (Rice and Wexler,
We would like to thank especially Margaret Echelbarger, who contributed significantly to data collection, transcription, and initial analyses presented at conferences, as well as provided significant comments on the present version; Lee Mavros-Rushton, coordinator of BDDP, who assisted with recruitment and in our testing sessions both with participants' behavioral issues and transportation. We are grateful to all of the participants and their families for taking part, and the Autism Resource Center of Central Massachusetts and Boston Children's Hospital for help with recruiting. We also thank all of the students in the Wexler Lab for help with collecting data; and audiences at the 29th Annual Symposium on Research in Child Language Disorders, Madison, WI, in June 2008; the 33rd Boston University Conference on Language Development, Boston, MA in November 2008; Autism Consortium Symposium, Boston, MA, in November 2008; COST Action A33, Let the Children Speak: Final Conference, London, UK, in January 2010; Autism Consortium Symposium, Boston, MA, in October 2010, where some of the findings were presented.
1The terms “tense marking” and “finiteness” will be used interchangeably throughout the paper to refer to the phenomenon that verbs in most main clauses in adult sentences must be marked for tense, which makes them finite.
2A further 29 children were recruited, but had to be excluded for various reasons (detailed here and in the footnotes to follow). Of these, 11 participants with ASD were excluded due to their inability to complete the battery.
3For 15 participants, confirmed diagnoses were not available due to difficulties with data sharing. On average, our study was performed with ASD participants 1.14 years (
4Three participants did not meet the criteria of either ADOS or ADI-R and were thus excluded despite their clinical diagnoses of Pervasive Developmental Disorder—Not Otherwise Specified (PDD-NOS).
5This classification left us with 14 “borderline” participants who scored at or above the 10th percentile on both vocabulary tests, but below the 10th percentile on TROG-2, with SS of 72–79, and thus could not be classified into either ALN or ALI (cf. Roberts et al.,
6Seventeen participants with ALN and 19 participants with ALI were included in the sample in Perovic et al. (
7For one ALI participant and one ALN participant, the KBIT Matrices scores were unavailable, leaving them with no matched TD controls.
8When we report the data that go beyond the major planned measure of this paper, that is finiteness rates, we compare ALN and ALI. We do not report results for TD. This is because in moving a laboratory, we lost the original data sheets for the TD participants. We already had their finiteness measures, per participant, but had not yet analyzed the extra measures (like null-subjects) that we calculated. Since we have the ALN measures, which show very little error on many of these responses, we can compare them to ALI.
9A reviewer made the interesting suggestion that instead of being instances of -
10For the remaining participants, no subjects were recorded on the answer sheets, likely because no subjects were produced. However, to be conservative, the responses from these participants were excluded from these counts.
11Note that the significance levels for our correlation analyses (here and in the next section) were not Bonferroni corrected; we will use them only in trying to observe particular patterns that might suggest specific hypotheses and further studies.
12We are grateful to a reviewer for this clarification of disruption and deviance, as well as for pointing out Thornton and Rombough's work to us.
13Utterances in this form, with a
14We are grateful to a reviewer for clarifying this aspect of deviance.
15It is important to also note that few studies investigate linguistic abilities in large numbers of children with ALI although there are regular references to ALI in the literature (e.g., Bishop et al.,
16A weaker formulation of ALI = ASD + SLI is possible. It might be proposed that (for some reason) the genes underlying ASD and SLI have a strong tendency to be inherited together, so that the chance of the co-occurrence of inheriting SLI if a child has ASD is much larger than the chance of inheriting SLI if a child does not have ASD. The statistical argument above does not count against such a formulation. Questions of grammatical deviance and rates of finiteness, however, are still relevant, counting against the hypothesis.
autism language impaired
autism language impaired—typically developing controls
autism language normal
autism language normal—typically developing controls
autism spectrum disorders
Agreement Tense Omission Model
chronological age
Clinical Evaluation of Language Fundamentals
Down syndrome
extended optional infinitive stage
Kaufman Brief Intelligence Test
mental age
mean length of utterance
nonsignificant
nonverbal intelligence quotient
optional infinitive
Peabody Picture Vocabulary Test
raw score
specific language impairment
standard score
typical development or typically developing
Rice/Wexler Test of Early Grammatical Impairment
Test of Reception of Grammar
Williams syndrome.