Voice onset time in Swedish children and adults.

Voice onset time (VOT) is a temporal acoustic parameter, which reflects the timing of speech motor control. The objective of the work was to obtain normative VOT data in Swedish children. Thus, 150 children aged 8-11 years old and 36 adults were audio-recorded when producing the plosives in minimal pairs. Measures were made using waveforms and spectrograms. Results show that Swedish children developed adult-like VOT values between 9 and 10 years. By the age of 10 years prevoicing was also found to be completely adultlike in length. The results indicate that all Swedish adults do not produce voiced plosives with prevoicing. No evident gender differences were found. The obtained VOT values can be used as normative data when assessing children with speech and language disorders.