Speech exposure at 3-months-old and communicative development in later infancy

Abstract

Exposure to language in infancy is a crucial part of infant communicative development. Infant-directed speech (IDS) refers to the way in which adults speak to babies, with a higher and more variable pitch and exaggerated vowels. It is part of most infants’ environment. Infants have been shown to prefer IDS over adult-directed speech (ADS). IDS helps older infants learn words and exposure to IDS predicts later language comprehension. Previous studies have investigated IDS experience and outcomes in older infants. IN this study, exposure to speech characteristic of IDS at the earlier age of 3 months was investigated as a predictor of later word comprehension. Audiovisual data was collected from the infants’ perspectives at 3 months and processed in linguistic software to quantify IDS exposure by measuring three variables: pitch range, glissando, and speech rate. Comprehension was measured using the MacArthur-Bates Communicative Development Inventory (MCDI) at 12 months. Pitch range and glissando had the greatest predictive value regarding the amount of words understood at 12 months, whereas speech rate was negatively predictive. These findings imply that speech containing higher pitch variability and a greater number of large pitch changes may help facilitate infant word comprehension.