Acoustic observations in young children's non-cry vocalizations

Area of Science:

• Pediatric Speech and Hearing
• Acoustic Phonetics
• Child Language Development

Background:

• Understanding typical vocal development in infants is crucial for identifying potential speech or voice disorders.
• Non-cry vocalizations provide valuable insights into early laryngeal function and phonatory capabilities.

Purpose of the Study:

• To investigate the occurrence and characteristics of specific acoustic features in the non-cry vocalizations of typically developing children.
• To determine if harmonic doubling (HD), fundamental frequency (F0) shift, and biphonation (Bp) are normal phonatory events in early childhood.

Main Methods:

• Retrospective analysis of 1200 non-cry vocalization samples from 14 children aged 11-25 months.
• Spectrographic examination to identify instances of HD, F0 shift, and Bp.
• Perceptual judgment of acoustic features to correlate with auditory perceptions like harshness and pitch breaks.

Main Results:

• Six percent of the analyzed vocalizations contained instances of HD, F0 shift, or Bp.
• These spectrographic features represent short-duration changes in fundamental frequency, indicating alterations in vocal fold states.
• HD and Bp were perceived as harsh, while F0 shift correlated with pitch breaks.

Conclusions:

• The observed frequency of harmonic doubling, fundamental frequency shift, and biphonation suggests these are normal phonatory events in the vocal patterns of healthy young children.
• These findings contribute to the understanding of normative laryngeal function during early vocal development.
• Further research can explore the developmental trajectory and potential clinical significance of these acoustic features.