Ekaterina Tomas

Purpose This study investigated methodological and theoretical aspects of using mean length of utterance (MLU) and its alternatives in cross-linguistic research and, in particular, its applicabilit...

Although the Developmental Language Disorder (DLD), also known as Specific Language Impairment in children has been the focus of unceasing scientific attention for decades, the nature and mechanisms of this disorder remain unclear. Most importantly, we still cannot reliably identify children requiring urgent intervention among other ‘late talkers’ at an early age and understand the high prevalence of comorbidity with psychiatric phenomena such as Autism Spectrum Disorder. One of the main reasons for this is the traditional ‘diagnosis-by-exclusion,’ resulting in heterogeneity of the DLD population. This paper proposes an alternative approach to the diagnosis, treatment and research of DLD, claiming that it is these children’s multiple deficits in neuropsychological development, which impede the spontaneous acquisition of their first language. Specifically, this review of the state-of-the-art in DLD research demonstrates deep and systematic interconnections between the speech and other higher cognitive functions developing in early childhood, including perception, attention and executive functions. In the proposed framework, speech is, therefore, considered as one of neuropsychological abilities, and the delay in its development is explained by other neuropsychological deficits, resulting in highly individual clinical profiles. By considering DLD as a complex neuropsychological syndrome, whose successful treatment depends on a holistic approach to diagnosis and intervention, we may significantly increase the efficacy of speech therapy, and also better understand the flexibility of the developing brain, its compensatory mechanisms and hence the comorbidity of DLD with psychiatric symptoms. Implications for using this paradigm in future scientific research are discussed.

Purpose: The aim of this article was to explore how the type of allomorph (e.g., past tense buzz [ d ] vs. nod [ əd ]) influences the ability to perceive and produce grammatical morphemes in children with typical development and with specific language impairment (SLI). Method: The participants were monolingual Australian English–speaking children. The SLI group included 13 participants (mean age = 5;7 [years;months]); the control group included 19 children with typical development (mean age = 5;4). Both groups performed a grammaticality judgment and elicited production task with the same set of nonce verbs in third-person singular and past tense forms. Results: Five-year-old children are still learning to generalize morphophonological patterns to novel verbs, and syllabic /əz/ and /əd/ allomorphs are significantly more challenging to produce, particularly for the SLI group. The greater phonetic content of these syllabic forms did not enhance perception. Conclusions: Acquisition of morphophonological patterns involving low-frequency allomorphs is still underway in 5-year-old children with typical development, and it is even more protracted in SLI populations, despite these patterns being highly predictable. Children with SLI will therefore benefit from targeted intervention with low-frequency allomorphs.

Morphophonological alternations can make target-like production of grammatical morphemes challenging due to changes in form depending on the phonological environment. This article explores the acquisition of morphophonological alternations involving the interacting patterns of vowel deletion and stress shift in Russian-speaking children (aged 4;0–7;11) using a ‘wug’ test with real and nonce words. Depending on the phonological context, participants were expected to either delete vowels (e.g. ko’mok_Nom,sg – kom’ka_Gen,sg) or preserve them (e.g. p^ji’lot_Nom,sg – p^ji’lota_Gen,sg). The results showed that children’s sensitivity to morphophonological patterns increases with age: 4-year-olds tended to preserve underlying vowels and stress across conditions, whereas older children demonstrated growing accuracy, at least with real words. Stressed vowels were more appropriately alternated and preserved across conditions, suggesting suprasegmental effects on the acquisition of segmental alternation patterns in Russian.

A growing body of research with typically developing children has begun to show that the acquisition of grammatical morphemes interacts not only with a developing knowledge of syntax, but also with developing abilities at the interface with prosodic phonology. In particular, a Prosodic Licensing approach to these issues provides a framework for understanding why children’s early use of grammatical morphemes is so variable. This in turn provides a means for making predictions, given the prosodic structure of a particular language and the location of a particular grammatical morpheme, if it is likely to be produced or not. Given that many of the patterns of development found in typically developing children are found in older children with Specific Language Impairment (SLI) as well, the Prosodic Licensing Hypothesis should provide a better understanding of some of the variable use of grammatical morphemes found in children with SLI.

Background: Five‐year‐olds with specific language impairment (SLI) often struggle with mastering grammatical morphemes. It has been proposed that verbal morphology is particularly problematic in this respect. Previous research has also shown that in young typically developing children grammatical markers appear later in more phonologically challenging contexts.Aims: The main aim was to explore whether grammatical deficits in children with SLI are morphosyntactic in nature, or whether phonological factors also explain some of the variability in morpheme production. The analysis considered the effects of the same phonological factors on the production of three different morphemes: two verbal (past tense ‐ed; third‐person singular ‐s) and one nominal morpheme (possessive ‐s).Methods & Procedures: The participants were 30 children with SLI (21 boys) aged 4;6–5;11 years (mean = 5;1). The data were collected during grammar test sessions, which consisted of question/answer elicitations of target forms involving picture props. A total of 2301 items were analysed using binary logistic regression; the predictors included: (1) utterance position of the target word, (2) phonological complexity of its coda, (3) voicing of the final stem consonant, (4) syllabicity (allomorph type) and (5) participant accounting for the individual differences in the responses.Outcomes & Results: The results showed a robust effect of syllabicity on the correct morpheme production. Specifically, syllabic allomorphs (e.g., She dresses) were significantly more challenging than the segmental ones (e.g., He runs) for all three morphemes. The effects of other factors were observed only for a single morpheme: coda complexity and voicing helped explain variability in past tense production, and utterance position significantly affected children's performance with the possessive. The participant factor also had a significant effect, indicating high within‐group variability ‐ often observed in SLI population.Conclusions & Implications: The systematic effect of syllabicity across both verbal and nominal morphemes suggests morphophonological influences in the grammatical development of children with SLI that cannot be fully explained by syntactic deficits. Poorer performance in producing syllabic allomorphs can be accounted for by much lower overall frequency of these forms, and by the ‘tongue‐twisting’ effect of producing similar segments in succession, as in added [ædəd], washes [wɒʃəz]. Interestingly, the greater acoustic salience of the syllabic allomorphs (an extra syllable) does not enhance children's abilities to produce them. These findings suggest that the interconnections between different levels of language have a stronger effect on the grammatical development of children with SLI than might be expected. Allomorphy should, therefore, be taken into account when designing language assessments and speech therapy, ensuring that children receive sufficient practice with the entire set of allomorphic variants.