The effects of menopause on voice onset time in Spanish Plosives

Voice onset time (VOT) is a well-known temporal aspect of speech production that is affected by a person’s language, age and sex. However, knowledge on the effects of female reproductive hormones on VOT is still scarce, especially concerning menopause, a biological developmental stage when reproductive endocrinological profiles change significantly. The present investigation compares VOT for voiced and voiceless consonants between pre- (n = 25) and postmenopausal (n = 27) Spanish speakers who are professional voice users with and without voice training, i.e., singers and schoolteachers, respectively. Clinical examinations, hormonal samples and audio recordings were carried out. The latter included carrier sentences containing three pairs of Spanish plosives (/b-p/; /d-t/; /g-k/) in an initial position of a word, followed by the vowel /a/. A principal component analysis and a subsequent hierarchical clustering analysis on principal components were both carried out to confirm correct allocation of participants into pre- and postmenopausal groups. High concentrations of pituitary hormones and low concentrations of androgens and progesterone defined hormonal clustering, confirming post-menopause and explaining 60 % of data variation. A Bayesian hierarchical beta regression distribution model was fitted to the data. For the postmenopausal group, a higher probability for a greater proportion of VOT was found, especially for consonants /b/ and /g/. One may conclude that females’ reproductive hormonal profiles influence VOT at menopause, an effect that seems to precede effects of ageing. Possible implications on work-related performance of singers and schoolteachers are discussed.