Longitudinal research on adolescent voice change in males.

Many of the characteristics and processes associated with adolescence are reasonably well understood; others are not. Still unanswered are questions about adolescent voice change. For example, when does the average child start the process; what changes result and what is their extent; when is it complete? Further, how closely do shifts in vocal level parallel, or even predict, the adolescent process? This project was carried out in order to obtain data which would complement available information on the subject and provide additional specificity about voice change and pubescence--at least for boys. To that end, a longitudinal study was conducted in which 48 males were tracked over a 5-year period. Voice measurements were made--including speaking fundamental frequency (SFF) and phonational frequency range (PFR)--as were others relating to physical size (height, weight, and six body dimensions). It was found that (1) stable adolescent voice change (AVC) measurements could be obtained, (2) maturation patterns appeared predictable on the basis of AVC changes, and (3) both the onset and duration of voice change extended over a longer period of time than had been previously thought.