BACKGROUND/AIM It is widely believed that 'creaky voice' ('creak', 'vocal fry', 'glottal fry') is increasingly prevalent among some English speakers, particularly among young American women. Motivated by the widespread and cross-disciplinary interest in the phenomenon, this paper offers a systematic review of peer-reviewed research (up to January 2019) on the prevalence of creaky voice in varieties of English. The review aimed to understand whose and what speech has been studied, how creaky voice prevalence has been measured, and what the findings collectively reveal. METHOD Literature was located by searching four electronic databases (ProQuest, PubMed, SCOPUS, Web of Science) and the proceedings of two recurrent conferences ('ICPhS' and 'SST'). Studies were included if they reported the prevalence of creaky voice in naturalistic samples of English spoken by vocally-healthy speakers. Reference lists of included studies were cross-checked. RESULTS Only ten studies meeting inclusion criteria were identified. All studies sampled a small number of speakers and/or short durations of speech. Nine were recent studies of American-English speakers, and many of these sampled young, female, college students. Across the ten studies, creaky voice was detected using three types of methods, and prevalence was calculated using five different formulae. The findings show that prevalence varies across groups, individuals, and contexts. However, the precise nature of this variability remains unclear due to the scarcity and methodological heterogeneity of the research. CONCLUSIONS This paper illustrated the application of systematic literature review methods in sociophonetic research-a field in which such methods are not common. The review found that creaky voice prevalence in English is not well understood, and that widespread claims of its recent increase among young American women have not been empirically confirmed. A number of specific limitations in the existing research are highlighted, which may serve as a guide for future research design.

中文翻译：

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各种英语中吱吱作响的声音（声母）的定量流行：文献的系统综述。

背景技术/目的人们普遍认为“吱吱作响的声音”（“吱吱作响的”，“发声的声音”，“声响的声音”）在一些说英语的人中，特别是在年轻的美国女性中越来越普遍。出于对该现象的广泛且跨学科的兴趣，本文提供了系统的同行评审研究（截至2019年1月），该研究涉及英语品种中普遍出现的吱吱作响的声音。审查旨在了解已研究了谁和哪种语言，如何测量语音发狂，以及所发现的结果。方法通过搜索四个电子数据库（ProQuest，PubMed，SCOPUS，Web of Science）和两次定期会议的记录（“ ICPhS”和“ SST”）来查找文献。如果研究报告了声音健康的说话者所讲英语的自然主义样本中普遍存在吱吱作响的声音，则将这些研究包括在内。交叉检查了纳入研究的参考清单。结果仅鉴定出符合入选标准的十项研究。所有研究都对少量说话者和/或较短的讲话时间进行了采样。九项针对美国英语使用者的最新研究，其中许多是年轻的女大学生。在这十项研究中，使用三种类型的方法检测到吱吱作响的声音，并使用五个不同的公式计算患病率。研究结果表明，患病率随群体，个人和环境的不同而不同。然而，由于研究的稀缺性和方法学的异质性，这种可变性的确切性质仍不清楚。结论本文阐述了系统的文献综述方法在社会语音研究中的应用，而该领域并不常见。该评论发现，英语的声音流行程度尚未得到很好的理解，并且尚未从经验上证实在美国年轻女性中这种声音普遍流行的广泛说法。重点介绍了现有研究中的许多特定限制，它们可以作为将来研究设计的指南。