Advaith Vijayasankaran

Investigating How Age Affects IDS Preference Among Monolingual and Bilingual Babies

Started May 8, 2025

Abstract or project description

This study examines how age and bilingualism, particularly the linguistic distance between a bilingual infant’s two languages, influence infants’ preference for infant-directed speech (IDS). IDS, distinguished by exaggerated prosody and simplified syntax, is known to facilitate early language development. While infants generally prefer IDS to adult-directed speech (ADS), prior research has produced mixed findings regarding the effects of age and bilingual experience on this preference. Using data from A Multilab Study of Bilingual Infants: Exploring the Preference for Infant-Directed Speech, which included 718 infants (333 bilingual, 384 monolingual) tested across 17 laboratories in seven countries, this study analyzed a lab-matched dataset to investigate these variables in greater depth and precision. Linear regression analyses conducted in Jamovi tested whether IDS preference (measured by diff, the difference between IDS and ADS looking times) varied as a function of age or language background. Results indicated no significant main effects of age or language group, nor a significant interaction between the two, on IDS preference. However, monolingual infants demonstrated significantly longer IDS looking times than bilingual infants, suggesting that extended attention to IDS does not necessarily imply a stronger relative preference for it. In a secondary analysis, linguistic distance was coded numerically based on the degree of linguistic difference between a bilingual infant’s languages. Although infants exposed to more linguistically distant language pairs exhibited a non-significant trend toward greater IDS preference, this relationship did not reach statistical significance. Overall, findings suggest that IDS preference remains stable across infancy and is largely unaffected by bilingualism or linguistic distance, challenging hypotheses that these factors meaningfully shape early speech perception. These results support the view that infants’ responsiveness to IDS may represent a universal, experience-independent mechanism for language learning. Future research using larger and unprocessed datasets could further clarify subtle developmental or cross-linguistic influences on IDS preference and inform early assessments of language development.