PONE-D-20-04317

Language experience in LSF development: Behavioural evidence from a sentence repetition task

PLOS ONE

Dear Mrs Bogliotti,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

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Many of the points raised are very straightforward, such as ensuring that the English is proofread by a native speaker and that stylistic conventions (such as the use of abbreviations, and using decimal points rather than commas (for example, 7.45, not 7,45) are obeyed. The remaining points mostly ask for additional information and explanation about the methods, together with recommendations for some additional statistical tests. I am sure that none of these changes will pose any problems and look forward to receiving your revised version. We would appreciate receiving your revised manuscript by Jun 11 2020 11:59PM. When you are ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

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Bencie Woll, PhD

Academic Editor

PLOS ONE

Additional Editor Comments:

The development of an SRT for French Sign Language is an imprtant step both for researchers of LSF and for practitioners seeking a suitable assessment tool for use in educational settings where children are acquiring LSF. The authors have made considerable changes in content and focus from the original drafts and this has led to a much-improved paper, with very positive reviews. Both reviewers, however, ask for a number of changes and additions of information before the paper can be finally accepted. All of these are very straightforward. I look forward to receiving the final revised version and to its publication.

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This research was partially supported by the Education, Audiovisual and Culture Executive Agency – EACEA (543264-LLP- 1-2013-1-ITKA2-KA2MP “SignMET” – Principal Investigator: Pasquale Rinaldi). Sign Language coders were paid by the EVASIGNE Project (Paris Lumière University Funding) (PI: Caroline Bogliotti & Marion Blondel)'

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Partly

Reviewer #2: Yes

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

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3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

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4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: No

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5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: The project team developed a sentence repetition task (SRT) in French Sign Language (LSF) and tested the psychometric soundness of the LSF-SRT. The authors found that children who are native signers made significantly more repetitions than non-native signers and that younger children made more errors than older children. These finds are consistent with the findings of other language fluency tests.

The introduction was well written with an appropriate literature review. The authors adequately and thoroughly described past research on the use of the SRT in signed languages and the cognitive processes that the test measures including how these tests are more sensitive to language fluency than working memory skills.

While the age ranges of the native and late signers appear similar, please compute and share the results of a t-test to show that the two groups did not differ in their chronological ages.

The actual AOA of the subjects were not listed in Table 1 except “native” or “late. It would be better to include the actual AOA. Table 1 seems to suggest that at least one of the “native” signers has deaf parents that sign Romanian SL at home. It is unclear why this child was included in this study as a native LSF signer. And, another subject has one parent that uses Greek Sign Language and the other uses SLF. Similarly, three of the children in the “non-native” group are from spoken language bilingual families. At the present, we do not know if the sign language acquisition trajectory is the same for children who grow up in a home that does not use the same spoken/written language used at school compared to those who grow up in a family that uses the same spoken/written language used at school. If all of these children were removed from the study, are the results the same?

How was the initial pool of 35 LSF sentences created? What were the qualifications of the two deaf adults that repeated the initial pool of 35 LSF sentences and provided judgements? Were they native signers? Do they have psychology or linguistic backgrounds? What was taken into consideration in the selection of the “best” or most natural 20 sentences?

The reviewer is happy that the authors included Table 2 to give readers an idea of how repetitions were evaluated. This is helpful for other teams who wish to develop an SRT in their local sign language.

A description of the coders’ backgrounds would be helpful if another team wants to replicate the study. Were the coders deaf and native SLF signers? Since each subjects’ repetitions were coded by two coders, please provide the inter-rater reliability between coders. This is an important piece of the test’s psychometric soundness and the authors have the data available.

The reviewer got confused when reading the percentage of repeated signs then the percentage of errors in repeated signs. The percentage of repeated signs analyses included signs that were repeated incorrectly but the reviewer was expecting the first analysis to be on correct repetitions. The authors did not appear to analyze the AOA and CA effects on correct repetitions without errors. This analysis needs to be conducted.

When the number of phonological errors was reported, was that the total sample number of errors (in case of native signers, 26 errors, SD = 12) or the mean number of errors per native signing subject? Please provide the mean but it was not clear if it was the mean or sum.

It was noted that the native signers used regional variations in their repetitions. It is difficult to develop an SRT with no possible regional variations. If the observed regional variations were the same among a number of native signers then the team might want to consider it an appropriate/correct response rather than an error. This makes the reviewer wonder about the test instructions—were the test takers told to make exact repetitions and given an example of a variation and told why it is wrong and necessary to give an exact repetition? Some other sign language SRTs do this to minimize variations in repetitions. Please describe your test instructions.

Since chronological age (CA) is a continuous variable but was transformed to a grouping variable for the ANOVA results. It might be worthwhile to include the correlation between CA and percent correct repetitions so the results could be compared to other SRT studies.

The operational definition of “frozen signs” needs to be provided and the significance of analyzing dominant and non-dominant hand classifiers. Since this is being analyzed, it would be appropriate to report how many of these subjects were right-hand dominant.

Adults were included in the study and were called “control.” But, they did not really serve as a control group. If anything, the native signers were the control group for the late signers. The data from the adult group could be kept or omitted for a different manuscript as it did not really help the authors document the psychometric soundness of the LSF-SRT for children unless the authors wanted to compare the results of young native signers with adult native signers.

The use of “late” for non-native signers has been criticized in the past because “late” sounds more like a judgement compared to “non-native,” please consider changing the terms.

Similar to the introduction, the discussion was thorough and helpful.

The authors suggest that the LSF-SRT is a tool that clinicians and educators could use in the future. But, the authors did not thoroughly describe who their coders were. If their coders were deaf native signers with linguistics knowledge, then it might not be possible for hearing professionals or non-native signers to code results similar to the coders in this study.

Editorial feedback: Line 111, SLI was mentioned but it should be spelled out the first time used for the naïve reader. And, 132, “SLI children” should be changed to “children with SLI” (also, see line 112). Specific Language Impairment was spelled out (without its abbreviation) in the final section, Future Work. Please consider revising.

Claims made the sentence that starts with line 190 should be cited.

The reviewer did not review earlier submissions of the manuscript but read the authors’ responses to the past reviewers’ comments. It appears that the authors addressed most of the past reviewers’ concerns. The manuscript does appear to be more focused on test development and validity than phonology. The authors do not talk about validity at all although their results provide partial support on the validity of the LSF-SRT that they developed.

Reviewer #2: The manuscript has the potential to offer a valuable addition to research into LSF, and the use of a sentence repetition task as an assessment tool. It contributes to and confirms previous findings, whilst helping to bring LSF study in-line with studies in other sign languages. The notable number of native LSF participants from deaf families included in the study is also commendable.

However, I believe there are several issues that need to be addressed by the authors before it would be suitable for publication.

General comments:

• I propose that the article be proofread and corrected by a native English speaker. Whilst the English is mostly clear and understandable, it is not currently at a suitable standard for publishing in PLOS ONE, with many errors and omitted words, so substantial editing is needed.

• Care needs to be taken with consistency in using abbreviations. e.g. LSF, SL and SLI are frequently used in both long and short form. e.g. line 180-181 “SL development” is immediately followed by “sign language development”

• Sections of the manuscript appear to be repetitious. Eg. the start of the discussion section, whilst intended as a recap for the reader, is very similar to the abstract.

Introduction

• Line 111 is the first mention of ‘SLI’ so please correct to “specific language impairment (SLI)” for clarity.

• Line 88 - Likewise, explain ‘ASL’ as ‘American Sign Language’ in the first instance for the reader, unless it can be assumed the readers will be familiar with the abbreviation.

Methodology

• Little information is given as to how the sentences for the SRT were created. Did the authors adapt sentences from other SRTs, or did they create new sentences? A pilot study is mentioned (line 313) from which 20 sentences were selected for their “naturalness”. I am unclear as to what is meant by this and think it requires some clarification. Given that the focus of the manuscript is the utilisation of an SRT, more information about the creation of the sentences would be useful. The description provided of the linguistic content of sentences, along with complexity level is good.

• Participants - the inclusion of 10 deaf native signing adults is a useful addition to the study for comparison, however limited information is given about them other than their age range. As they are being used as a comparative group, please provide more detail on their ages (and mean age), and sex etc.

• Procedure - line 337 states testing took place in the school library, suggesting that all of the participants attended the same school. If this is the case, it may be a relevant point to make for the study as it offers some control to the language environment/experience of all of the children whilst they are at school. It may be a strength to the study to make this clear, if it is the case.

• If the children do all attend the same school, Table 1 on page 14 detailing children’s linguistic environment should clarify that this refers to their “home language environment”.

• Line 380-381 First states there are 6 coders, then states there are 2 coders - I assume the 2 independent coders were used for inter-rater reliability, but this is slightly unclear, please rephrase and add the reliability rating if available.

Results

• The asterisks indicating significance levels appear to be missing from the figures.

• Lines 431 and 432 contain commas instead of decimal points (2,84% instead of 2.84%). Proofreading needed.

Discussion

• Lines 671-674 appear to state that there are no known developmental stages of language acquisition in deaf children and that the current study is a first attempt to address this issue. This statement is not true. I assume that the authors intend this statement to relate to LSF, but it is unclear to the reader so needs to be clarified or rewritten.

• If lines 671-674 are, in fact, in relation to LSF, I am not convinced that this study addresses the question of developmental stages of language acquisition in LSF, beyond the finding that native or early LSF acquisition results in higher accuracy on the task.

• Line 650 - the participants’ fluency was rated by coders on a scale of 0-5. Were the coders blind to which group the participants were in (native or late learners), and was any inter-rater reliability undertaken? Only the average score for early signers is provided in the text, please provide the rest of the data for this measurement.

• Lines 539-540 regarding regionalisms - were participants all tested in the same region, or from different areas of France? if participants were all from the same area (or school) would the authors predict differing regionalisms in their signing?

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Reviewer #1: Yes: pH

Reviewer #2: No

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Language experience in LSF development: Behavioral evidence from a sentence repetition task

PONE-D-20-04317R1

Dear Dr. Bogliotti,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

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Kind regards,

Bencie Woll, PhD

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

The authors have dealt with the reviewers’ comments and the paper now reads well and makes an important contributionn to studies of LSF acquisition. There still remain a few minor points made by the reviewers that should to be corrected in the final version.:

A few minor grammatical errors:

Line 22 - should read "10 adult signers were evaluated" instead of "was evaluated"

Line 42 - should read "on a case by case basis"

Line 56 - insert 'be' so the sentence reads "may be disturbed"

Line 65 - should read "no SRT study has..." instead of had.

Inconsistency in the use of ‘sign language’ vs SL.

Reviewer 2’s Comment 36. Please add a brief clarification.

The authors should briefly address Reviewer 1’s comment about the importance of the home spoken language.

The reporting of intercode comparisons should briefly report the correlation.

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

Reviewer #2: (No Response)

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2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

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3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

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4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

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5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

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6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: The authors developed a sentence repetition task in LSF and provided data on how native and non-native deaf signers performed on the test. They included age of LSF acquisition, chronological age, and error types in the analyses. The results shed light on the LSF fluency of deaf children of different language experiences and provide psychometric support for the use of the test in research and clinical settings.

I had the privilege to review the previous submission and this revision. I am impressed, overall, how much the authors took into consideration the reviewers comments in each manuscript revision. The present manuscript is much better than the previous one and I hardly have any new criticisms of the draft.

I think the sample could be more "clean" (and replicable) if the native signers had the same LSF experience at home and the non-native signers had the same French experience at home. I disagree with the authors' response that since the participants are deaf, the home spoken language is irrelevant. In the USA, deaf children from hearing English-speaking and Spanish-speaking families perform differently in school. While this does not mean that home language itself might have an effect but other factors that are associated with not having the dominant spoken language at home might have an effect on children's overall language development. I believe that if the two samples (native, non-native) could be more homogeneous within group by omitting those with different language experiences than the rest in the group. If such participant exclusion does not change the results of the study then this would improve the SRT replicability and cross-linguistic comparisons in future studies. The authors appear to disagree.

I would like to thank the authors for computing intercoder comparisons. I am more used to seeing the correlation being reported, rather than a t-test, to show the inter-rater reliability. Please provide the correlation as well in the final manuscript.

Reviewer #2: The authors have addressed all of the reviewers comments and cleared up the few previous areas of confusion. I would like to congratulate the authors on an interesting paper which will be a valuable addition to studies in LSF.

There remain only very minor editorial issues to be addressed from the previous review:

Comment 24 - the manuscript has been corrected by a native English speaker and the clarity of the manuscript has been much improved. There are only a few minor grammatical errors that remain:

Line 22 - should read "10 adult signers were evaluated" instead of "was evaluated"

Line 42 - should read "on a case by case basis"

Line 56 - insert 'be' so the sentence reads "may be disturbed"

Line 65 - should read "no SRT study has..." instead of had.

Comment 25 - the authors say that they have chosen to use the long-form of "sign language" (as opposed to the abbreviation SL) thought the manuscript. However, from page 4 onwards, a mixture of both forms are still used throughout.

Comment 36 - I acknowledge and appreciate that the authors have clarified that they are specifically referring to LSF in line 698. However, the previous sentence which begins the paragraph on line 695-697 still needs to be clear that they are referring to LSF and not language in general, which is how the sentence currently reads.

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7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: Yes: pH

Reviewer #2: No