Vowel Acoustic Space Development in Children: A Synthesis of Acoustic and Anatomic Data

Abstract

Vowel development is expressed as follows: (a) establishment of a language-appropriate acoustic representation (e.g., F1-F2 quadrilateral or F1-F2-F3 space), (b) gradual reduction in formant frequencies and F1-F2 area with age, (c) reduction in formant-frequency variability, (d) emergence of male-female differences in formant frequency by age 4 years with more apparent differences by 8 years, (e) jumps in formant frequency at ages corresponding to growth spurts of the VT, and (f) a decline of f0 after age 1 year, with the decline being more rapid during early childhood and adolescence. Questions remain about optimal procedures for VT normalization and the exact relationship between VT growth and formant frequencies. Comments are included on nasalization and vocal fundamental frequency as they relate to the development of vowel production.