The development of sex/gender-specific /s/ and its relationship to gender identity in children and adolescents

Abstract

A growing body of literature has revealed sex/gender differences in the acoustics of the sibilant fricative /s/. It has been suggested that some of this sex/gender-related variation might be socially motivated and acquired. However, the necessary developmental research to corroborate this proposal is absent from the literature. To address this, we examined sex/gender differences in the production of /s/ acoustics in relation to children׳s physical growth and gender identity. The speech production of children and adolescents aged 4–16 years old was recorded. Additionally, the physical height was measured and gender identity was evaluated through a parent-filled questionnaire. Three acoustic measures were calculated that describe the mean, standard deviation, and skewness of the spectral frequencies of /s/. Results indicated that gender identity played a key role in mediating the difference in /s/ acoustics between boys and girls for all three acoustic measurements. Additionally, for adolescent boys, gender identity explains within-gender variation in /s/. Our results thus highlight the importance of social-behavioral factors in the development of sex/gender difference in /s/ production.