Humans are one of the mammalian species that exhibit vocal sexual dimorphism. Hormonal changes at puberty have distinct effects on laryngeal growth, resulting in different vocal fold morphology across females and males. The respective effects on speaking fundamental frequency (SFF) have been exhaustively investigated in young males, suggesting a drastic decrease of SFF during puberty. Notably, also females undergo vocal change during puberty, resulting in a drop of SFF by several semi-tones. While this notion was investigated previously, empirical validation with a comprehensive longitudinal data set is outstanding.

Here, we present longitudinal SFF data for a unique database of 101 female choristers aged 8 to 16 years (mean age: 12.4 ± 1.9 years), captured every six months from 1999 to 2017. Based on availability, between two and 15 recordings could be made for the individual choristers, totaling 623 data acquisitions, with an average of about 6.17 sessions per chorister. After a brief period of spontaneous speech (not analyzed), the choristers read a phonetically balanced text („Arthur the Rat“) in conversational loudness. Phonation was simultaneously documented with acoustic and electroglottographic (EGG) recordings. SFF was estimated with Praat’s autocorrelation algorithm, using EGG signals for corroboration.

Pending further analysis, preliminary statistical tests suggest a drop of median SFF from about 260 Hz at age 8 to about 222 Hz at age 16, following a polynomial trend of SFF = 0.352 · age · age – 12.944 · age + 340.479 [Hz] (R-squared = 0.123), corroborating earlier cross-sectional studies. SFF as a function of age can be approximated by simple string model, substituting previously determined age-varying vocal fold length data (cf. Hirano et al., 1981). However, the low correlation coefficient of 0.123 suggests large individual variability. SFF analysis of our unparalleled longitudinal data corpus thus promises to produce deeper insights into the overall and the individual vocal development of pubescent females.