Effects of socio-economic status on infant native and non-native phoneme discrimination.

Infants undergo fundamental shifts in perception that are reported to be critical for language acquisition. In particular, infants' perception of native and non-native sounds begins to align with the properties of their native sound system. Thus far, empirical evidence for this transition - perceptual narrowing - has drawn from socio-economically and linguistically narrow populations from limited world regions. In this study, infants were sampled across diverse socio-economic strata and linguistic development in Singapore. One hundred and 16 infants were tested on their ability to discriminate both a native phonetic contrast (/ba/ versus /da/) and a non-native Hindi contrast (/ta/ versus /ʈa). Infants ranged in age from 6 to 12 months. Associations between age and discrimination varied by contrast type. Results demonstrated that infants' native sensitivities were positively predicted by family SES, whereas non-native sensitivities were not. Maternal socio-economic factors uniquely predicted native language sensitivity. Findings suggest that infants' sensitivity to native sound contrasts is influenced by their family socio-economic status. RESEARCH HIGHLIGHTS: We investigated effects of socio-economic status on infant speech perception. Infants were tested on native and non-native speech discrimination. Socio-economic status predicted native speech discrimination. Maternal occupation was a key predictor of native speech discrimination.