{"title":"Determining Optimal Talker Variability for Nonnative Speech Training: A Systematic Review and Bayesian Network Meta-Analysis.","authors":"Xiaojuan Zhang, Bing Cheng, Yu Zou, Yang Zhang","doi":"10.1044/2024_JSLHR-24-00599","DOIUrl":null,"url":null,"abstract":"<p><strong>Purpose: </strong>This meta-analysis study aimed to determine the optimal level of talker variability in training to maximize second-language speech learning.</p><p><strong>Method: </strong>We conducted a systematic search for studies comparing different levels of talker variability in nonnative speech training, published through July 2024. Two independent reviewers screened studies for eligibility, extracted data, and assessed the risk of bias. A Bayesian network meta-analysis was implemented to estimate relative effect sizes of different talker variability training conditions and rank these conditions by their posterior probabilities using surface under the cumulative ranking curve (SUCRA) values.</p><p><strong>Results: </strong>A total of 32 studies involving 998 participants were analyzed to compare six training conditions based on the number of talkers. Using a no-training control condition as the reference and excluding the outlier, the random-effects model showed that training with six talkers was most effective (SUCRA = 94%, standardized mean difference [SMD] = 2.09, 95% CrI [1.30, 2.89]), exhibiting moderate between-study heterogeneity (posterior median <i>SD</i> = 0.60, 95% CrI [0.39, 0.90]). However, when considering both the format of talker presentation and training exposure, the conditions with four talkers presented in blocks across training sessions (SUCRA = 77%, SMD = 1.47, 95% CrI [0.92, 2.10]), two talkers intermixed during sessions (SUCRA = 75%, SMD = 1.65, 95% CrI [0.24, 3.03]), and six talkers intermixed (SUCRA = 72%, SMD = 1.38, 95% CrI [0.97, 1.79]), all showed similarly high effectiveness with only minor differences.</p><p><strong>Conclusions: </strong>This systematic review and Bayesian network meta-analysis demonstrate for the first time that optimizing talker variability in nonnative speech training requires a careful balance between the number of talkers and the presentation format. The findings suggest that a moderate level of talker variability is most effective for improving second-language speech training outcomes.</p><p><strong>Supplemental material: </strong>https://doi.org/10.23641/asha.28319345.</p>","PeriodicalId":51254,"journal":{"name":"Journal of Speech Language and Hearing Research","volume":" ","pages":"1-18"},"PeriodicalIF":2.2000,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Speech Language and Hearing Research","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1044/2024_JSLHR-24-00599","RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"AUDIOLOGY & SPEECH-LANGUAGE PATHOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Purpose: This meta-analysis study aimed to determine the optimal level of talker variability in training to maximize second-language speech learning.
Method: We conducted a systematic search for studies comparing different levels of talker variability in nonnative speech training, published through July 2024. Two independent reviewers screened studies for eligibility, extracted data, and assessed the risk of bias. A Bayesian network meta-analysis was implemented to estimate relative effect sizes of different talker variability training conditions and rank these conditions by their posterior probabilities using surface under the cumulative ranking curve (SUCRA) values.
Results: A total of 32 studies involving 998 participants were analyzed to compare six training conditions based on the number of talkers. Using a no-training control condition as the reference and excluding the outlier, the random-effects model showed that training with six talkers was most effective (SUCRA = 94%, standardized mean difference [SMD] = 2.09, 95% CrI [1.30, 2.89]), exhibiting moderate between-study heterogeneity (posterior median SD = 0.60, 95% CrI [0.39, 0.90]). However, when considering both the format of talker presentation and training exposure, the conditions with four talkers presented in blocks across training sessions (SUCRA = 77%, SMD = 1.47, 95% CrI [0.92, 2.10]), two talkers intermixed during sessions (SUCRA = 75%, SMD = 1.65, 95% CrI [0.24, 3.03]), and six talkers intermixed (SUCRA = 72%, SMD = 1.38, 95% CrI [0.97, 1.79]), all showed similarly high effectiveness with only minor differences.
Conclusions: This systematic review and Bayesian network meta-analysis demonstrate for the first time that optimizing talker variability in nonnative speech training requires a careful balance between the number of talkers and the presentation format. The findings suggest that a moderate level of talker variability is most effective for improving second-language speech training outcomes.
期刊介绍：
Mission: JSLHR publishes peer-reviewed research and other scholarly articles on the normal and disordered processes in speech, language, hearing, and related areas such as cognition, oral-motor function, and swallowing. The journal is an international outlet for both basic research on communication processes and clinical research pertaining to screening, diagnosis, and management of communication disorders as well as the etiologies and characteristics of these disorders. JSLHR seeks to advance evidence-based practice by disseminating the results of new studies as well as providing a forum for critical reviews and meta-analyses of previously published work.
Scope: The broad field of communication sciences and disorders, including speech production and perception; anatomy and physiology of speech and voice; genetics, biomechanics, and other basic sciences pertaining to human communication; mastication and swallowing; speech disorders; voice disorders; development of speech, language, or hearing in children; normal language processes; language disorders; disorders of hearing and balance; psychoacoustics; and anatomy and physiology of hearing.
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