A Brief History of Vocal Fry: Terminology, Definitions, and Sentiment.

Purpose: Definitions and opinions of "vocal fry" have varied over time. The purpose of this review is to examine the history of research on vocal fry, identify and define the terminology used to describe vocal fry in the clinical literature, and examine the history of sentiment regarding the use of vocal fry. This historical narrative review aims to establish a foundation to inform future clinical research by identifying both advances and evidence gaps in the literature on vocal fry. Method: A historical narrative review was conducted. Results: The term "vocal fry" initially appeared in the clinical literature in 1958, although some early work suggests that sentiment regarding this voice quality appeared at least as early as 1935. Vocal fry was considered a voice disorder until research in the 1960s found that it is acoustically and perceptually distinct from diagnosed "harshness." Based on acoustic and physiological evidence, vocal fry was defined as a normal phonation register through much of the work in the 1970s. Current descriptions of vocal fry vary. While it is known to occur in the phrase-final position to mark phrase boundaries in nonpathological speech, current sentiment regarding vocal fry is mixed. Some clinical works list it as an aberrant or potentially pathological voice quality and report negative perception of its use, while others report using it as a therapeutic task in the setting of voice rehabilitation. In addition to changes in sentiment, various terms have been associated with the voice quality either as a synonym or to describe a related quality. Conclusions: The term "vocal fry" has had varying sentiments and multiple perceptual, physiological, and acoustic qualities associated with it. Additionally, terminology has varied over time and across researchers. Future research on vocal fry should clearly define the voice quality in order to allow for more direct comparison and make connections to clinical application.