Gendered speech development in early childhood: Evidence from a longitudinal study of vowel and consonant acoustics

Adults rate the speech of children assigned male at birth (AMAB) and assigned female at birth (AFAB) as young as 2.5 years of age differently on a scale of <i>definitely a boy</i> to <i>definitely a girl</i> (Munson et al., 2022), despite the lack of consistent sex dimorphism in children's speech production mechanisms. This study used longitudinal data to examine the acoustic differences between AMAB and AFAB children and the association between the acoustic measures and perceived gender ratings of children's speech. We found differences between AMAB and AFAB children in two acoustic parameters that mark gender in adult speech: the spectral centroid of /s/ and the overall scaling of resonant frequencies in vowels. These results demonstrate that children as young as 3 years old speak in ways that reflect their sex assigned at birth. We interpret this as evidence that children manipulate their speech apparatus volitionally to mark gender through speech.