Author:

Keywords:

Social Sciences, Psychology, Developmental, Linguistics, Psychology, Experimental, Psychology, SPEECH-LIKE VOCALIZATIONS, VOCAL DEVELOPMENT, MEAN LENGTH, INFANT, UTTERANCE, Age Factors, Child Language, Child, Preschool, Humans, Infant, Longitudinal Studies, Speech, Video Recording, 11 Medical and Health Sciences, 17 Psychology and Cognitive Sciences, 20 Language, Communication and Culture, Speech-Language Pathology & Audiology, 42 Health sciences, 47 Language, communication and culture, 52 Psychology

Abstract:

Various measures for identifying the onset of babbling have been proposed in the literature, but a formal definition of the exact procedure and a thorough validation of the sample size required for reliably establishing babbling onset is lacking. In this paper the reliability of five commonly used measures is assessed using a large longitudinal corpus of spontaneous speech from forty infants (age 0 ; 6-2 ; 0). In a first experiment it is shown that establishing the onset of babbling with reasonable (95%) confidence is impossible when the measures are computed only once, and when the number of vocalizations are not equal for all children at all ages. In addition, each measure requires a different minimal sample size. In the second experiment a robust procedure is proposed and formally defined that permits the identification of the onset of babbling with 95% confidence. The bootstrapping procedure involves extensive resampling and requires relatively few data.