Does morphological richness account explain morphological ability of children with specific language impairment?
Abstract
This study focuses on the acquisition of morphology in preschool children with specific language impairment (SLI). According to the previous research, children with SLI have specific problems in this language area.
We apply the morphological richness account (MRA; Leonard, 2014) as a theory explaining this deficit in Czech, replicating the study design by Lukács et al. (2009); they tested the theory on Hungarian. The MRA theory presupposes that limitations in morphology in children are a result of the interaction between limited processing capacity of children with SLI and structure of the acquired language.
The first hypothesis assumes that children should primarily devote their limited processing capacity to the acquisition of the most prevalent grammatical cues in language, i. e. morphology in Czech. Therefore, they should be only delayed in the acquisition of these grammatical cues.
Nevertheless, MRA presupposes that more extensive deficits occur, when inflections encode more dimensions and require greater demands on processing - which is problem of verbs in Czech, but not of nouns. The third assumption is that children have some knowledge of inflections, so they should make errors, which differ from target morpheme in one dimension (near-miss error).
Fourth MRA hypothesis presupposes that if near-miss error is not used, inflection should be more frequent. The aim of this research was to examine the ability to inflect nouns and verbs in 17 children with SLI (from 5 to 7 years old) in comparison with 17 younger typically developing (TD) children (from 3 to 4 years old).
Each TD child was matched to child with SLI on gender and results in a receptive vocabulary task. Modified sentence imitation was used to examine the children's ability to use morphological markers (target morphemes were masked by cough and children had to repeat the sentences and complete the target word).
Accuracy in the completions of target morphemes was scored for grammaticality. In testing MRA hypothesis, we found that the first hypothesis was confirmed by this research - children with SLI were as proficient as TD children in completion of target nouns (z=1,33, p=0,18).
Contrary to the second presupposition, children with SLI were much less successful in completions of nouns than verbs (like TD children; z = 7,487, p < 0.001) and in completion 81 of target verbs were as accurate as TD children (z=1,40, p=0,16). Third hypothesis was confirmed by data - near-miss errors were prevalent, but relationship with frequency in non near-miss errors was not approved.
In contrast with the Hungarian study, this research confirmed the applicability of the MRA theory to Czech only to some extent. Our findings are important for presuppositions of acquisition of language in children with SLI in Slavic languages, which can be different from languages of other language families.
References Leonard, L. B. (2014).
Children with specific language impairment. MIT press.
Lukács, A. G., Leonard, L.
B., Kas, B., & Pléh, C. (2009). The use of tense and agreement by Hungarian-speaking children with language impairment.
Journal of Speech, Language, and Hearing Research, 52(1), 98-117.