Biomedical subjects

Laurence B Leonard

Publications and source records attributed to Laurence B Leonard.

At least 19 recordsLinked to original sources

PubMed2006

The production of finite and nonfinite complement clauses by children with specific language impairment and their typically developing peers.

The purpose of this study was to explore whether 13 children with specific language impairment (SLI; ages 5;1-8;0 [years;months]) were as proficient as typically developing age- and vocabulary-matched children in the production of finite and nonfinite complement clauses. Preschool children with SLI have marked difficulties with verb-related morphology. However, very little is known about these children's language abilities beyond the preschool years. In Experiment 1, simple finite and nonfinite complement clauses (e.g., The count decided that Ernie should eat the cookies; Cookie Monster decided to eat the cookies) were elicited from the children through puppet show enactments. In Experiment 2, finite and nonfinite complement clauses that required an additional argument (e.g., Ernie told Elmo that Oscar picked up the box; Ernie told Elmo to pick up the box) were elicited from the children. All 3 groups of children were more accurate in their use of nonfinite complement clauses than finite complement clauses, but the children with SLI were less proficient than both comparison groups. The SLI group was more likely than the typically developing groups to omit finiteness markers, the nonfinite particle to, arguments in finite complement clauses, and the optional complementizer that. Utterance-length restrictions were ruled out as a factor in the observed differences. The authors conclude that current theories of SLI need to be extended or altered to account for these results.

Analysis of Variance↗

PubMed2006

Nonword repetition and sentence repetition as clinical markers of specific language impairment: the case of Cantonese.

PURPOSE: Recent research suggests that nonword repetition (NWR) and sentence repetition (SR) tasks can be used to discriminate between children with SLI and their typically developing age-matched (TDAM) and younger (TDY) peers. METHOD: Fourteen Cantonese-speaking children with SLI and 30 of their TDAM and TDY peers were compared on NWR and SR tasks. NWR of IN nonwords (CV combinations attested in the language) and OUT nonwords (CV combinations unattested in the language) were compared. SR performance was compared using 4 different scoring methods. RESULTS: The SLI group did not score significantly lower than the TDAM group on the test of NWR (overall results were TDAM = SLI > TDY). There were nonsignificant group differences on IN syllables but not on OUT syllables. The results do not suggest a limitation in phonological working memory in Cantonese-speaking children with SLI. The SR task discriminated between children and their TDAM peers but not between children with SLI and their TDY peers matched for mean length of utterance. CONCLUSIONS: SR but not NWR discriminates between children with SLI and their TDAM peers. Poorer NWR for English-speaking children with SLI might be attributable to weaker use of the redintegration strategy in word repetition. Further cross-linguistic investigations of processing strategies are required.

Analysis of Variance↗

PubMed2006

Response time in 14-year-olds with language impairment.

PURPOSE: To determine whether children with language impairment were slower than typically developing peers at age 14, and whether slowing, if present, was similar across task domains; whether differences in response time (RT) across domains were the same for children with specific language impairment (SLI) and nonspecific language impairment (NLI); and whether RT performance at age 9 predicted performance at age 14. METHOD: Fourteen-year-old children with SLI (n = 20), NLI (n = 15), and typical development (NLD; n = 31) were administered several linguistic and nonlinguistic speeded tasks. The children had received the same tasks at age 9. RT performance was examined. RESULTS: Both the SLI and the NLI groups were significantly slower than the NLD group in motor, nonverbal cognitive, and language task domains, and there was no significant difference among domains. Individual analyses showed that most, but not all, children with SLI and NLI were slower than the NLD group mean. Slowing at age 9 and age 14 were moderately correlated. CONCLUSIONS: The results suggest that slow RT is a persistent characteristic of many children with language impairment; however, the nature of the relationship between RT and language performance requires further investigation.

Adolescent↗

PubMed2006

Tense and agreement morphemes in the speech of children with specific language impairment during intervention: phase 2.

PURPOSE: The goals of this investigation were to determine whether treatment assists children with specific language impairment (SLI) in the use of grammatical morphemes that mark tense and agreement and whether treatment gains influence the children's use of other, untreated morphemes. METHOD: Twenty-five children with SLI participated in 96 intervention sessions designed to facilitate the children's use of third-person singular -s or auxiliary is/are/was. RESULTS: The children showed significantly larger gains on the target forms than on control forms (e.g., past tense -ed) that were monitored but not included in intervention. Along with possible treatment-related generalization across morpheme types, there was also evidence of one morpheme type influencing another when neither was the target of intervention. CONCLUSIONS: Although the results provide clear evidence for intervention effects, it appeared as if maturational factors also played a role. The findings are discussed in terms of their implications for treatment and for characterizing development in SLI.

Child Language↗

PubMed2006

Effects of acoustic manipulation on the real-time inflectional processing of children with specific language impairment.

PURPOSE: This study reports the findings of an investigation designed to examine the effects of acoustic enhancement on the processing of low-phonetic-substance inflections (e.g., 3rd-person singular -s, possessive -s) versus a high-phonetic-substance inflection (e.g., present progressive -ing) by children with specific language impairment (SLI) in a word recognition, reaction time (RT) processing task. The effects of acoustic enhancement on the processing of the same morphemes as well as an additional morpheme (comparative -er) were examined in an offline grammaticality judgment task. The grammatical function of 1 of the higher-phonetic-substance inflections, -ing, was presumed to be hypothesized relatively early by children; the function of the other, -er, was presumed to be hypothesized relatively late. METHOD: Sixteen children with SLI (age(M) = 9 years;0 months) and 16 chronological age (CA; age(M) = 8;11) children participated. For both tasks, children listened to sentences containing the target morphemes as they were produced naturally (natural condition) or with acoustic enhancement (enhanced condition). RESULTS: On the RT task, the children with SLI demonstrated RT sensitivity only to the presence of the high-substance inflection, irrespective of whether it was produced naturally or with enhancement. Acoustic enhancement had no effect on these children's processing of low-substance inflections. The CA children, by contrast, showed sensitivity to low-substance inflections when they were produced naturally and with acoustic enhancement. These children also showed sensitivity to the high-substance inflection in the natural condition, but in the enhanced condition they demonstrated significantly slower RT. On the grammaticality judgment task, the children with SLI performed worse than the CA children overall and showed especially poor performance on low-substance inflections. Acoustic enhancement had a beneficial effect on the inflectional processing of the children with SLI, but it had no effect on CA children. CONCLUSION: The findings are interpreted to suggest that the reduced language processing capacity of children with SLI constrains their ability to process low-substance grammatical material in real time. This factor should be considered along with any difficulty that might be attributable to the grammatical function of the inflection.

Child↗

PubMed2005

The expression of aspect in Cantonese-speaking children with specific language impairment.

Previous studies of verb morphology in children with specific language impairment (SLI) have been limited in the main to tense and agreement morphemes. Cantonese, which, like other Chinese languages, has no grammatical tense, presents an opportunity to investigate potential difficulties for children with SLI in other areas of verb morphology, via scrutiny of elements of its aspectual system. The performance of 3 groups of children (n = 15 in each group)--preschoolers with SLI, typically developing same-age peers, and younger, typically developing peers--was compared in procedures designed to elicit aspect forms. The children with SLI were less likely to produce both perfective and imperfective aspect markers. It is suggested that reasons for these findings are to be found in the sparse morphology of Cantonese and in the nonobligatory nature of these forms.

Analysis of Variance↗

PubMed2004

Predicting tense: finite verb morphology and subject pronouns in the speech of typically-developing children and children with specific language impairment.

According to the AGREEMENT/TENSE (Agr/Tns) OMISSION MODEL, children's failure to produce finite verb morphemes represents the selection of an optional infinitive form, in which tense and/or agreement is not specified. When agreement is specified, nominative case is licensed. Following the assumptions of this model, a child's utterance such as She run reflects a failure to specify tense only, given that the subject pronoun shows nominative case. We tested this assumption in two studies through the analysis of spontaneous speech samples from young typically-developing (TD) children and children with specific language impairment (SLI). In Study 1, 15 children were included (TD aged 2;1-3;11, SLI aged 4;0-6;2); in Study 2, 33 children were included (TD aged 2;5-3;11, SLI aged 3;6-6;9). We determined whether there was a relationship between the children's use of past tense -ed and their use of third person singular -s and copula is when nominative case was also used. Because nominative case was used, any failures to produce third person singular -s and copula is should be attributable to tense and not agreement. Such use should therefore be related to the children's use of -ed which presumably hinges on tense only. However, a relationship was not found in the speech of either group of children. This was true both for the children in each group who were consistent in using nominative case pronouns and for those who were not. Possible reasons for these findings are discussed.

Child↗

PubMed2004

The comprehension of wh-questions in children with specific language impairment.

Current theories of specific language impairment (SLI) in children fall into 2 general classes: those that attribute SLI to processing limitations and those that attribute the disorder to deficits in grammatical knowledge. In this study, the authors examined children's comprehension of subject and object Wh-questions because they offer the means of determining the relative contribution to performance of knowledge and of processing. Comprehension of subject and object Wh-questions presumably requires knowledge of grammatical movement. However, through manipulation of the length of the questions, it is also possible to vary the processing demands of the questions. If a simple deficit in knowledge of movement is involved, children should show poorer comprehension on object questions than on subject questions, regardless of sentence length. However, if processing limitations are involved, length should affect comprehension of object questions but not subject questions. Children with SLI and typically developing (TD) children matched on receptive vocabulary test scores participated in a comprehension task consisting of short and long subject and object Wh-questions. The two groups performed similarly on short questions, each showing high accuracy in both subject and object conditions. However, the children with SLI showed poorer performance on long object questions compared to long subject questions. They were also less accurate on long object questions than were children in the TD group. We argue that demands on linguistic processing abilities play an important role in the difficulties experienced by children with SLI.

Child↗

PubMed2004

Tense and agreement in the speech of children with specific language impairment: patterns of generalization through intervention.

Thirty-one children with specific language impairment participated in 48 intervention sessions designed to assist them in the use of 3rd-person singular -s or auxiliary is/are/was. Gains in the use of these target forms were significantly greater than gains on developmentally comparable morphemes serving as control forms. Untreated verb forms that mark both tense and agreement showed greater change during the intervention period than did past -ed. The findings suggest that by gaining skill in the use of morphemes that mark both tense and agreement, the children were able to identify and acquire other morphemes in the language that mark both of these features. This increase in sensitivity did not appear to apply to forms in the language that express tense only.

Analysis of Variance↗

PubMed2004

Questions without movement: A study of Cantonese-speaking children with and without specific language impairment.

English-speaking children with specific language impairment (SLI) appear to have special difficulty in the use of who-object questions (e.g., Who is the girl chasing?). It has been argued that problems related to grammatical movement may be responsible for this difficulty. However, it is also possible that the lower frequency of who-object questions relative to who-subject questions also plays a role. In this study, the use of who-object and who-subject questions by children with SLI who were acquiring Cantonese as their 1 st language was examined. In Cantonese, the surface form of who-object questions (e.g., hung4zai2 sek3 bin1go3? [Bear kiss who?]) reflects the same subject, verb, object order typically used for declarative sentences, and a movement account provides no basis for expecting special difficulties with such questions. As in English, however, Cantonese who-object questions occur less frequently than do who-subject questions. A comparison of preschoolers with SLI, typically developing same-age peers, and younger, typically developing peers revealed that the children with SLI were less accurate in using who-object questions than either of the other participant groups yet showed no differences from these groups in the use of who-subject questions (e.g., bin1go3 sek3 zyu1zyu1? [Who kiss Piglet?]). The implications of these findings for current accounts of SLI are discussed, and the idea that input frequency and animacy may play a larger role than is often assumed is suggested.

Analysis of Variance↗

PubMed2003

The use of grammatical morphemes reflecting aspect and modality by children with specific language impairment.

Children with specific language impairment (SLI) have well-documented problems in the use of tense-related grammatical morphemes. However, in English, tense often overlaps with aspect and modality. In this study, 15 children with SLI (mean age 5;2) and two groups of 15 typically developing children (mean ages 3;6 and 5;3) were compared in terms of their use of previously studied morphemes in contexts that more clearly assessed the role of aspect. The children's use of less frequently studied morphemes tied to modality or tense was also examined. The children with SLI were found to use -ing to mark progressive aspect in past as well as present contexts, even though they were relatively poor in using the tense morphemes (auxiliary was, were) that should accompany the progressive inflection. These children were inconsistent in their use of third person singular -s to describe habitual actions that were not occurring during the time of their utterance. However, the pattern of the children's use suggested that the source of the problem was the formal tense feature of the inflection, not the habitual action context. The children's use of modal can was comparable to that of the typically developing children, raising the possibility that the modality function of possibility had been learned without necessarily acquiring the tense feature of this morpheme. These children's proficiency with can suggests that their bare verb stem productions should probably not be re-interpreted as cases of missing modals. Together these findings suggest that the more serious tense-related problems seen in English-speaking children with SLI co-occur with a less impaired ability to express temporal relations through aspect and modality.

Child↗

PubMed2003

Surface forms and grammatical functions: past tense and passive participle use by children with specific language impairment.

Children with specific language impairment (SLI) use past tense -ed in fewer obligatory contexts than younger normally developing children matched for mean length of utterance (MLU). In this study, the use of passive participle -ed (e.g., kissed in The frog got kissed by the kitty) as well as past tense -ed was examined in children with SLI, normally developing children matched for age (ND-A), and normally developing children matched for MLU (ND-MLU). The children with SLI used both past tense -ed and passive participle -ed in fewer obligatory contexts than bath the ND-A and the ND-MLU children. Only the children with SLI had greater difficulty with past tense -ed than with passive participle -ed. The pattern of findings indicates that the surface properties of -ed cannot adequately account for the past tense -ed difficulty shown by the children with SLI. However, the fact that the children with SLI were less consistant than the ND-MLU children in using passive participle -ed suggests that either the surface properties of -ed are responsible for a portion of the difficulty or these children have a separate, non-tense-related deficit in the area of verb morphology.

Child↗

PubMed2003

Grammatical morpheme effects on MLU: "the same can be less" revisited.

Studies of children with specific language impairment (SLI) often include 2 comparison groups of typically developing children--a group matched according to age and a group matched according to mean length of utterance (MLU). In these studies, both groups of typically developing children often perform better than the SLI group. For many of these investigations, grammatical morpheme use constitutes the dependent measure. The use of grammatical morphemes requires longer utterances than the failure to use these morphemes. If children with SLI show less use of grammatical morphemes than typically developing children matched for MLU, shouldn't they produce some other detail of language more frequently than the MLU-matched group? In this article, the authors report 2 studies showing that such offsetting effects are not necessary in principle, given the nature of MLU. The implications of these findings are discussed.

Case-Control Studies↗

PubMed2002

Lexical diversity in the spontaneous speech of children with specific language impairment: application of D.

The lexical diversity of children with specific language impairment (SLI) (ages 3 years 7 months to 7 years 3 months) was compared to that of normally developing same-age peers and younger normally developing children matched according to mean length of utterance in words (MLUw). Lexical diversity was calculated from spontaneous speech samples using D, a measure that uses repeated calculations of type-token ratio (TTR) to estimate how TTR changes as the speech samples increase in size. When D computations were based on 250-word samples, developmental differences were apparent. For both children with SLI and typically developing children, older subgroups showed higher D scores than younger subgroups, and subgroups with higher MLUws showed higher D scores than subgroups with lower MLUws. Children with SU did not differ from same-age peers. At lower MLUw levels, children with SLI showed higher D scores than younger typically developing children matched for MLUw. The developmental sensitivity of D notwithstanding, comparisons using 100-utterance samples, in which the number of lexical tokens varied as a function of the children's MLUws, and comparisons between 250- and 500-word samples revealed the possible influence of sample size on this measure. However, analysis of the effect sizes using smaller and larger samples revealed that D is not affected by sample size to the degree seen for more traditional measures of lexical diversity.

Child↗

PubMed2002

Grammatical morphologic development in pediatric cochlear implant users may be affected by the perceptual prominence of the relevant markers.

The goal of this study was to test 2 hypotheses about language development in pediatric cochlear implant (CI) users. The "language instinct" hypothesis states that children with CIs will develop language in the same sequence as children with normal hearing, but in a delayed fashion. In other words, noun plurals will develop first, and the use of the uncontractible copula and regular past tense will follow. An alternative hypothesis (the "perceptual prominence" hypothesis) is that the pattern of language development in CI users will be strongly affected by the perceptual prominence of the relevant morphological markers. This hypothesis predicts that the uncontractible copula will develop first, followed by noun plurals, and then by regular past tense. A sentence completion task was used to measure the performance of 9 pediatric CI users and compare it to that of several groups of children with normal hearing. The results from the CI users were consistent with the perceptual prominence hypothesis. In particular, the scores for the copula probe were higher than those for the noun plural probe for 8 of the 9 CI users. This result represents a rather striking inversion with respect to the usual development pattern in children with normal hearing and even in children with specific language impairment. If the perceptual prominence hypothesis receives further support in future studies, clinicians who work in language rehabilitation of CI users may choose to target those aspects of grammar that are less acoustically prominent to these children. In addition, and from a theoretical standpoint, these results suggest that although there may well be an innate language acquisition mechanism, patterns of language development can be strongly affected by the acoustic input.

Acoustics↗

PubMedDate not supplied

Fast mapping of verbs by children with specific language impairment.

Two studies examined preschoolers' ability to assign verb interpretations to nonsense words encountered in conjunction with novel actions. Experiment 1 examined the ability of children with specific language impairment (SLI) and younger, normally developing peers to glean a very interpretation when the name of the figure performing the novel action was already known. The two groups of children performed in a similar, accurate fashion. Experiment 2 required preschoolers to rely exclusively on morphosyntactic information to determine whether the novel word represented an object or action. When provided with redundant morphosyntactic cues, children with SLI and language- and age-matched peers succeeded in identifying the novel words that referred to objects but not those that referred to actions. Only the age-matched normal peers were above chance levels when a noun interpretation depended on a single grammatical morpheme (e.g., 'We want the koob' versus 'We want to koob'). The findings suggest that preschoolers, whether or not they have language impairment, have difficulty using morphosyntactic information to bootstrap verbs. Furthermore, redundant but not single morphosyntactic cues facilitate the bootstrapping of nouns.

Child↗

PubMedDate not supplied

Specific language impairment in Italian: the first steps in the search for a clinical marker.

Recent studies of children with specific language impairment (SLI) have identified language measures that seem quite accurate in distinguishing preschool-age children with SLI from their normally developing peers. However, the studies have focussed exclusively on English, and it is clear from the literature that the SLI profile varies between languages. This paper reports on three studies designed to assess the utility of particular language measures for Italian. In the first two studies, it was found that a composite measure based on the use of definite singular articles and third-person plural inflections showed good sensitivity and specificity in distinguishing Italian-speaking children with SLI from their typically developing peers. The third study showed that the same composite can be applied successfully to individual cases of SLI. Some of the additional steps needed to evaluate this composite measure are discussed.

Case-Control Studies↗

PubMedDate not supplied

Clinical markers for specific language impairment in Italian: The contribution of clitics and non-word repetition.

BACKGROUND: The discovery of clinical markers for specific language impairment (SLI) in children can assist in the accurate identification of children with this disorder, and in a description of the disorder's phenotype for genetic study. One challenge to this type of research is the fact that languages vary in the most salient symptoms of SLI. This study focuses on Italian. AIMS: To determine whether three measures--the use of third-person plural inflections, the use of direct-object clitics and non-word repetition--are successful in distinguishing Italian-speaking children with SLI from their typically developing peers. METHODS & PROCEDURES: Eleven preschool-aged children with SLI, 11 same-age typically developing peers and 11 younger typically developing children participated in the study. The third-person plural inflection and direct-object clitic tasks required the children to describe drawings in response to prompts provided by the examiner. In the non-word repetition task, the children repeated non-words ranging from one to four syllables in length. OUTCOMES & RESULTS: All three measures proved successful either singly or in combination, with direct-object clitics and non-word repetition showing the highest sensitivity and specificity. CONCLUSIONS: Additional research should be pursued to replicate and extend these findings. Along with the potential clinical value of the findings, the results suggest that difficulties with non-final weak syllables--a problem that would adversely affect all three measures--may be an important part of the SLI profile in Italian.

Case-Control Studies↗