Thesis Defense Announcement

School of  Communication  Sciences and Disorders announces the Final Thesis Defense of

Janine Peca

for the Degree of Master of Arts

March 25, 2022at 2:30 PM in Community Health Building, Room 3062

Advisor: Dr. D. Kimbrough Oller

Role of Sex in Rate of Infant Vocalization and Canonical Babbling

ABSTRACT: "- A female language advantage has been widely reported, although it has not been consistently shown across the literature. When the effect is statistically significant, it has been typically small and not necessarily consistent by age or type of language measure. Looking for evidence of the female language advantage in the first year is challenging as the age-range has been rarely investigated for sex differences in language-related behaviors. In the present study, 46 infants (28 males, 18 females) were recorded at 4, 6, 8, 10, 12, 14, 16, and 18 months. Infant utterances were categorized distinguishing vegetative sounds (coughs, sneezes etc.) and fixed signals (cries and laughs) from protophones, the presumable precursors to speech. Only the protophones were counted in the determination of volubility. The number of utterances per min was treated as the “volubility” measure. Each protophone could consist of one or more syllables, where syllables were defined as audible rhythmic beats, a concept that applies both to canonical (baba, dadi, etc.) and non-canonical (e.g., any sequence of vowels only) utterances. The number of canonical syllables across the session was divided by the total number of syllables (canonical syllables / canonical + non-canonical syllables) to yield the canonical babbling ratio for each session. The findings indicate no clear sex advantage in either canonical babbling ratio or volubility during the first 18 months of life."