Contribution of Nonverbal Cognitive Skills on Bilingual Children’s Grammatical Performance: Influence of Exposure, Task Type, and Language of Assessment

Round 1

Reviewer 1 Report

This study investigated the contributions of nonverbal cognitive abilities on morphosyntactic performance in bilingual children. It also examined how these contributions varied by the type of grammatical task (cloze vs. narrative), the language of assessment (L1 vs. L2), and the amount of language exposure. The authors found that processing speed and working memory differentially contributed to the children’s performance on different grammatical tasks. Moreover, these contributions varied by language dominance and amount of exposure. The results indicate that cognitive skills differentially contribute to morphosyntactic tasks depending on the language of the task.

This manuscript would be of interest to researchers who are considering individuals differences in bilingual language processing. Its relevance to the readership of Languages is also suitable. However, the paper would benefit from some major revisions, especially with how the study is framed. Below, I outline my comments that may be useful to the authors.

1. The introduction is missing a thorough literature review and critical rationales for conducting this type of investigation. The information does not flow logically, making it difficult to understand the motivation of the study. The section on bilingualism and development (pg. 1) is sparse and confusing. There is a lot more that can be said about bilingual language and cognitive development. Moreover, the links being drawn between processing capacities, language exposure, and morphosyntactic performance are unclear.
2. The section on cognitive systems in development (pg. 2) is also vague. Why are the authors interested specifically in working memory (WM) and processing speed? The authors state that WM encompasses both domain-general and domain-specific components, so why then are they describing it as “nonverbal cognitive skills”? Again, the link between (nonverbal) cognitive abilities and language skills is not clearly laid out.
3. There have also been numerous studies examining morphosyntactic processing and working memory, which have not been referenced at all. This is strange given that it’s one of the main study questions. This should then lead up to the new contributions that the present study makes.
4. The section on cognition and exposure does not really discuss the role of language exposure, and how examining it is important/adds something new.
5. The Present Study section has incomplete sentences. Authors have not included references to critical statements in the introduction. E.g., page 3, line 91; page 3, line 104-105; page 2, line 58, and more.
6. Why were these specific ages chosen?
7. Scores on the nonverbal IQ test have not been reported. While the sample includes children who may have DLD, it would be good to see how TD and DLD children are performing on the various cognitive and linguistic tasks, because children with a language disorder may show different patterns in the hierarchical regressions. Did the authors conduct separate analyses for the two groups of children? Moreover, the means for morphosyntactic ability are fluctuating around 50%, which is quite low, and some children have an accuracy of 0. Were children excluded based on performance on these tasks? What does an SES score of 0 mean?
8. The discussion was much easier to follow than the introduction. It would benefit from a short recap of the major findings in the first paragraph, and then delve into the findings more deeply.

Author Response

Please see attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

This study presents original empirical data that contributes adequatly to the intended field, namely, the understanding of the interaction of cognition with linguistic performance by bilingual children. The manuscript provides a reasonable theoretical background and, to my understanding, appropriate information about the data presented and its statistical analysis.

There are, however, some defects in the manuscript, which in my opinion entail the need for modifications.

Regarding the changes I would suggest in the content, one of the main obstacles to acquiring a complete understanding of the research presented is the lack of specific details and examples of the tasks involved. The reader wonders, throughout, exactly what was done by the participants in the cloze and narrative tasks mentioned. In fact the omission of showing the items, which could- I hope- be done in an appendix, substantially affects the clarity of the article. If the tasks cannot be added in full, at least example items would be necessary, to an extent at which the reader can fully perceive what the study consisted of and the results actually mean.

Another important area that shoud be improved is the explicit description of the context of the study somewhere within the introductory sections. The reader only discovers a few vague mentions about the sociolinguistic and educational context of the participants towards the end of the paper (discussion, limitations of the study...). However, to understand the study itself, this kind of contextualisation is needed from the beginning. 

As regards the formal issues, I attach suggestions for some corrections needed. They refer to some of the sentences and paragraphs which must necessarily be corrected to make the text comprehensible, as well as other, minor issues to help the authors improve the overall editing.

Comments for author File: Comments.pdf

Author Response

Please see the attachment. 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

I thank the authors for considering my suggestions and making several changes to the manuscript to address them. The paper shows much improvement in its organization, especially in the Introduction – the rationale of the study and the literature review flow much better now. Most of my concerns about this manuscript have been resolved. I only have a few minor suggestions before this manuscript is recommended for publication.

1. On page 2, line 57 – For the line “Research by our labs and others”, the authors only cite themselves. It would be helpful to cite studies from these other labs.
2. Page 3 on working memory – you can add another study that examined the differential contributions of non-verbal working memory to morphosyntactic processing (grammaticality judgment task) in school-aged monolingual and simultaneous bilingual children. Gangopadhyay, I., Davidson, M. M., Weismer, S. E., & Kaushanskaya, M. (2016). The role of nonverbal working memory in morphosyntactic processing by school-aged monolingual and bilingual children. Journal of experimental child psychology, 142, 171-194.
3. Unless I’m misreading Table 2, the nonverbal IQ scores are not reported there or anywhere else in the manuscript. Also, the manuscript states that 2 subtests of the UNIT used were Symbolic memory and Cube design, but in the Author’s Response document it says Processing Speed and Working Memory. I’m sure it’s the former, but please include these scores in the manuscript in the correct Table.
4. Page 18, line 515 – Remove “In Summary” and just start with “The current study found….”

Author Response

Please see the attachment.

Author Response File: Author Response.pdf