Listener agreement on phonetic segments in early infant vocalizations

Area of Science:

• Linguistics
• Developmental Psychology
• Speech Science

Background:

• Assessing early infant vocalizations is crucial for understanding language development.
• Listener reliability in transcribing noncry, nonlanguage vocalizations presents methodological challenges.

Purpose of the Study:

• To evaluate interjudge and intrajudge agreement in phonetic transcriptions of infant vocalizations.
• To determine how listener agreement varies with infant age and transcription criteria.

Main Methods:

• Collected over 1,000 noncry, nonlanguage vocalizations from four female infants (7-21 months).
• Three trained listeners provided phonetic transcriptions.
• Assessed agreement using identical segment match and feature-match criteria, focusing on oral stops.

Main Results:

• Listener agreement varied significantly based on infant age and the agreement criterion used.
• Interjudge agreement showed a slight increase with infant age, potentially due to more speech-like vocal output.
• Identical segment match criteria yielded agreement below 60%, while feature-match criteria for oral stops showed higher reliability.

Conclusions:

• Listener reliability is a critical factor in the validity of auditory descriptions of infant vocal behavior.
• The choice of transcription criteria significantly impacts agreement rates.
• Findings have implications for refining methods used to analyze and describe early vocal development.