| Author: | Fu, Nga Ching |
| Title: | Nonword repetition in children with developmental language disorder : revisiting the case of Cantonese |
| Advisors: | Chan, Angel (CBS) Chen, Sarah (CBS) |
| Degree: | M.Phil. |
| Year: | 2024 |
| Subject: | Language disorders in children Chinese language -- Acquisition Cantonese dialects -- Acquisition Hong Kong Polytechnic University -- Dissertations |
| Department: | Department of Chinese and Bilingual Studies |
| Pages: | 129 pages : color illustrations |
| Language: | English |
| Abstract: | Background: Nonword repetition (NWR) has been advocated as a cross-linguistic clinical marker of Developmental Language Disorder (DLD; Bishop et al., 1996; Conti-Ramsden et al., 2001; Dollaghan & Campbell, 1998), due to its ability to discriminate children with DLD and those with typical development (TD) cross-linguistically, even in the context of bilingualism (Schwob et al., 2021). Cantonese has been the sole cross-linguistic exception, where NWR does not differentiate between TD children and those with DLD (Leung, 2010; Stokes et al., 2006). No studies have followed-up with this line of research, thus it remains unknown whether the divergent findings on Cantonese are based more heavily on typological differences between Cantonese and other previously examined languages, or methodological factors in Cantonese NWR studies. This thesis revisits NWR in Cantonese in three studies. Study I: Study I tested the hypothesis that the previous lack of significant findings on Cantonese NWR may be related to certain aspects of nonword stimuli design, including low levels of nonword lexicality and long nonword length. Three novel sets of NWR stimuli, which take into account factors known to affect NWR performance and group differentiation, were reported. Sixteen TD-DLD pairs of monolingual Cantonese-speaking children repeated two sets of High-Lexicality nonwords, and one set of Low-lexicality nonwords, which could be further analysed on sub-lexicality, based on CV combination attestedness (i.e., whether nonword syllables contained CV combinations that are attested in Cantonese). Children with DLD scored significantly below their TD peers, and effect sizes showed that nonwords with high levels of lexicality and sub-lexicality offered greater TD/DLD group differentiation, suggesting that Cantonese is not a true cross-linguistic exception in NWR. Future work could aim to replicate the present findings on a larger sample size, verify whether TD/DLD group differences are still captured by NWR in younger, Cantonese-speaking children, and examine the diagnostic accuracy of this NWR test. Study II: Following positive findings on monolingual Cantonese-speaking children reported in Study I, Study II investigated whether Cantonese NWR stimuli are able to avoid disadvantaging bilingual second language (L2) TD children, compared to monolingual TD (MonTD) children, as L2-TD children are at risk of being misclassified as children with language disorder in NWR, due to having reduced language knowledge and experience in the testing language to support NWR. NWR performance in 19 MonTD, 19 monolingual DLD (MonDLD) and 19 bilingual L1-Urdu-L2-Cantonese TD children (L2-TD) was examined on three sets of language-specific nonwords (reported in Study I) and one set of quasi-universal nonwords. When NWR accuracy was scored at whole-nonword level, language-specific, High-Lexicality nonwords captured group differences between DLD and TD groups (both monolingual and L2), while not disadvantaging the L2-TD group, compared to MonTD children. When NWR accuracy was scored at syllable level, quasi-universal, CL-NWR nonwords were the only set of stimuli that did not disadvantage L2-TD children relative to MonTD children, while still yielding significant group differences between the MonDLD and L2-TD groups. These findings provide evidence from a typologically distinct and understudied language that NWR has potential to disentangle the effects of language impairment (in MonDLD) and bilingualism (in L2-TD), and has potential to be further developed into clinically informative tools for DLD. Future studies can explore how an L2-DLD group performs relative to the examined groups, explore alternative bilingual groups of children acquiring other L1-L2 combinations, and explore sensitivity and specificity of Cantonese NWR in a bilingual context. Study III: With a recent study suggesting that sub-lexical representations may have a facilitative effect on NWR, above and beyond that of lexical representations (Szewczyk et al., 2018), Study III examined whether sub-lexicality in Cantonese NWR stimuli affected Cantonese-speaking children’s NWR performance and TD/DLD group differentiation. Data on NWR accuracy of 19 DLD-TD pairs of monolingual speaking children were analysed with two measures of sub-lexicality – CV combination attestedness, as positive first findings have been reported on this sub-lexical measure (both in Stokes et al., 2006, and Study I); and neighbourhood density (ND) of syllables, a newly proposed sub-lexical measure, as ND has been suggested as a strong cue to Cantonese word-likeness. Both measures significantly predicted NWR performance in Cantonese-speaking children, with ND of Syllables being a stronger predictor. CV combination attestedness interacted with participant group, where only syllables with attested CV combinations captured significant TD/DLD group differences. There was no evidence that ND of Syllables affected the degree of TD/DLD group differentiation in these Cantonese-speaking children. These findings suggest that sub-lexical representations play a crucial role in Cantonese NWR, either alongside or above and beyond the influence of lexical representations. Future studies can examine whether ND of Syllables predict NWR performance in children acquiring other languages, to confirm whether the findings on this novel sub-lexical measure can be generalised cross-linguistically; and also examine an additional sub-lexical measure, phonotactic probability, as a predictor of NWR performance in Cantonese-speaking children, in addition to the two examined measures. Conclusions: Cantonese is not a true cross-linguistic exception in NWR - NWR is able to capture significant group differences between Cantonese-speaking children with and without DLD, and Cantonese CL-NWR nonwords, as well as Cantonese language-specific High-Lexicality nonwords, demonstrated potential to disentangle the effects of language experience and language impairment. Factors affecting NWR accuracy in children acquiring other languages also affect children acquiring Cantonese, particularly in terms of nonword lexicality and sub-lexicality. The findings suggest that Cantonese NWR stimuli have the potential to be developed into clinically informative assessment tools for DLD in both monolingual and bilingual Cantonese-speaking children, but further research is needed to examine whether the present findings can be replicated in a larger sample size, generalised to younger children and bilingual children acquiring languages other than Urdu as their first language; and sensitivity and specificity of Cantonese NWR tests will also need to be examined for further development of NWR tasks into clinical assessment tools. |
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| Access: | open access |
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