Order effects in English and Urdu speaking infants’ and adults’ discrimination of non-native consonants: Urdu Affricate /tʃ/-/tʃʰ/ and English approximant-fricative /w/-/v/ contrasts

This thesis examines the decline in non-native consonant discrimination at the end of the first year and perceptual asymmetries that were identified in course of experiments. In Study 1 & 2, 7- and 11-month-old monolingual infants from English speaking homes were tested on the Urdu affricate contrast /tʃʰ/ and /tʃ/. The order of presentation was counterbalanced. Younger infants discriminated the contrast, whereas older infants only showed discrimination when the non-native aspirated affricate /tʃʰ/ was presented first. This led to Study 3, in which the 11-month-olds from Study 2 were tested again at 15 months of age on the same Urdu affricate contrast, with a different word pair, with similar results. In order to test if the same results could be found in infants from a different language background, Study 4 tested bilingual infants from Urdu speaking homes at two age groups, 7- and 11-months of age, on non-native English /w/ vs. /v/. Study 4 found order effect irrespective of age. In both age groups, the discrimination score was higher when the unfamiliar /w/ was presented first. Lastly, in order to find out if these order effects are maintained in adulthood, monolingual English and bilingual Urdu adults were tested in Study 5 on both native and non-native /w/ vs /v/ and /tʃ/ vs /tʃʰ/ contrasts. Only Urdu adults showed asymmetry for the non-native English contrast. These asymmetries can be interpreted in light of the Magnet theory (Kuhl 1986; Kuhl 1991), which explains how prototypicality of a given token and the order in which tokens are presented effects discrimination in a speech perception task.