Modal verbs with and without tense: A study of English- and Cantonese-speaking children with specific language impairment

Background: Surprizingly little is known about the use of modal auxiliaries by children with specific language impairment (SLI). These forms fall within the category of grammatical morphology, an area of morphosyntax that is purportedly very weak in children with SLI. Aims: Three studies were conducted to examine the use of modal auxiliaries by preschool-aged children with SLI. Methods & Procedures: In each study, probe tasks were designed to create contexts that encouraged the use of modals to express the modality functions of ability and permission. In Studies 1 and 3, English-speaking children participated. In Study 2, the participants were Cantonese-speaking children. In each study, three groups of children participated: A group exhibiting SLI, a group of younger typically developing children (YTD), and a group of (older) typically developing children (OTD) matched with the SLI group according to age. Outcome & Results: In Study 1, English-speaking children with SLI were as proficient as YTD children, though less proficient than OTD children in the use of the modal can to express the modality functions of ability and permission. In Study 2, the same modality functions were studied in the speech of SLI, YTD and OTD groups who were speakers of Cantonese. In this language, tense is not employed, and therefore the modality function could be examined independent of formal tense. Results similar to those of Study 1 were obtained. Study 3 again studied SLI, YTD and OTD groups in English to determine whether the children's expression of ability differed across past (could) and non-past (can) contexts. The results for can replicated the findings from Study 1. However, the children with SLI were significantly more limited than both the YTD and OTD groups in their use of could. Conclusions: The results suggest that most children with SLI have access to modality functions such as ability and permission. However, the findings of Study 3 suggest that they may have a reduced inventory of modal forms or difficulty expressing the same function in both past and non-past contexts. These potential areas of difficulty suggest possible directions for intervention. © 2007 Royal College of Speech & Language Therapists.link_to_subscribed_fulltex

The production of passives by children with specific language impairment: Acquiring English or Cantonese

The production of passive sentences by children with specific language impairment (SLI) was studied in two languages, English and Cantonese. In both languages, the word order required for passive sentences differs from the word order used for active sentences. However, English and Cantonese passive sentences are quite different in other respects. We found that English-speaking children with SLI were less proficient than both same-age and younger typically developing peers in the use of passives, although difficulty could not be attributed to word order or a reliance on active sentences. Cantonese-speaking children with SLI proved less capable than same-age peers in their use of passive sentences but at least as proficient as younger peers. The implications of these cross-linguistic differences are discussed. © 2006 Cambridge University Press.link_to_subscribed_fulltex

Modelling the effect of an occupant on displacement ventilation with computational fluid dynamics

International audienceDisplacement ventilation of a room with an occupant is modelled using computational fluid dynamics (CFD) and compared against experimental data. The geometry of the experimental manikin is accurately represented in the CFD model to minimise potential errors from using a simplified form. Modelling thermal radiation from the manikin is found to be important and calculations using a radiation model show good agreement with experimental data. The influence of turbulence modelling is considered and a comparative study is made between an unsteady Reynolds-averaged approach (URANS) and detached-eddy simulation (DES). The results show that the URANS and DES give similar predictions with the DES results in slightly better agreement with the experimental data. The realistic manikin geometry is required to give accurate heat transfer and contaminant exposure predictions; such geometries can be handled with relative ease using current grid generation tools and CFD solvers

Extra-linguistic influences on sentence comprehension in Italian-speaking children with and without specific language impairment.

BACKGROUND: Many children with specific language impairment (SLI) have deficits in sentence comprehension. These deficits are usually attributed to limitations in the children’s understanding of syntax or the lexical items contained in the sentences. In this study, we examine the role that extra-linguistic factors can play in these children’s sentence comprehension. AIMS: In this study, extra-linguistic demands on sentence comprehension were manipulated directly by varying the nature of the materials used. METHODS & PROCEDURE: Forty-five Italian-speaking children participated: 15 with SLI (M age = 4;5), 15 typically developing children matched for age (TD-A, M age = 4;5), and 15 younger typically developing children matched according to language comprehension test scores (TD-Y, M age = 3;9). The children responded to sentence comprehension items that varied in their length and/or in the number and type of foils that competed with the target picture. OUTCOME & RESULTS: The TD-A children were more accurate than the TD-Y children and the children with SLI, but, for all groups, accuracy declined when task demands increased. In particular, sentences containing superfluous adjectives (e.g., Il topo bello copre l’uccello allegro “The nice mouse covers the happy bird” where all depicted mice were nice and all birds were happy) yielded higher scores than similar sentences in which each adjective had to be associated with the proper character (e.g., Il cane giallo lava il maiale bianco “The yellow dog washes the white pig” where foils included a yellow dog washing a pink pig, and a brown dog washing a white pig). Many errors reflected recency effects, probably influenced by the fact that adjectives modifying the object appear at the end of the sentence in Italian. CONCLUSIONS & IMPLICATIONS: Differences between conditions were observed even when lexical content, syntactic structure, and sentence length were controlled. This finding suggests the need for great care when assessing children’s comprehension of sentences. The same syntactic structure and lexical content can vary in difficulty depending on the number and types of foils that are used in combination with the target picture