Melanie Schreiner, Nicole Altvater-Mackensen and Nivedita Mani

Early word segmentation in naturalistic environments: Limited effects of speech register

Infancy

We examined 7.5‐month‐old infants' ability to segment words from infant‐ and adult‐directed speech (IDS and ADS). In particular, we extended the standard design of most segmentation studies by including a phase where infants were repeatedly exposed to target word recordings at their own home (extended exposure) in addition to a laboratory‐based familiarization. This enabled us to examine infants' segmentation of words from speech input in their naturalistic environment, extending current findings to learning outside the laboratory. Results of a modified preferential‐listening task show that infants listened longer to isolated tokens of familiarized words from home relative to novel control words regardless of register. However, infants showed no recognition of words exposed to during purely laboratory‐based familiarization. This indicates that infants succeed in retaining words in long‐term memory following extended exposure and recognizing them later on with considerable flexibility. In addition, infants segmented words from both IDS and ADS, suggesting limited effects of speech register on learning from extended exposure in naturalistic environments. Moreover, there was a significant correlation between segmentation success and infants' attention to ADS, but not to IDS, during the extended exposure phase. This finding speaks to current language acquisition models assuming that infants' individual attention to language stimuli drives successful learning.