Developmental aspects of formant frequency and bandwidth in infants and toddlers.

Average formant frequency and formant bandwidth values are reported in a cross-sectional sample of 20 children between 4 and 25 months of age. With the exception of a slight rise in F1 at 18 months of age, average F1 and F2 values changed little during the time period, while the average bandwidths for F1 (B1) and F2 (B2) were found to significantly decrease as age increased. The pattern observed for both average formant frequencies and formant bandwidths were attributed to developmental reconfiguration of the vocal tract.