Development of the child's voice: premutation, mutation.

Voice range profile (VRP) measurement was used to evaluate the vocal capabilities of 180 children aged between 4 and 12 years without voice pathology. There were 10 boys and 10 girls in each age group. Using an automatic VRP measurement system, F0 and SPL dB (lin) were determined and displayed two-dimensionally in real time. The speaking voice, the shouting voice and the singing voice were investigated. The results show that vocal capabilities grow with advancing age, but not continuously. The lowering of the habitual pitch of the speaking voice as well as of the entire speaking pitch range occurs for girls between the ages of 7 and 8, for boys between 8 and 9. A temporary restriction of the minimum vocal intensity of the speaking voice (the ability to speak softly) as well as of the singing voice occurs for girls and for boys at the age of 7-8. A decrease of the maximum speech intensity is found for girls at the age of between 7 and 8, for boys between 8 and 9. A lowering of the pitch as well as of the intensity of the shouting voice occurs for both sexes from the age of 10. In contrast to earlier general opinion we note for girls a stage of premutation (between the age of 7 and 8) with essentially the same changes seen among boys, but 1 year earlier. The beginning of the mutation can be fixed at the age of 10-11 years.