A cross-language comparison of vowel perception in English-learning and German-learning infants

Studies of cross-language consonant discrimination have shown a shift from a language-general to a language-specific pattern during the first year of life. Recently, the same pattern of change was observed for English-speaking infants' discrimination of two non-native vowel contrasts (Polka and Werker, 1994). The present study was designed to provide a more direct assessment of language-specific influences on infant vowel contrast perception. In experiment 1 adults were tested on a German (non-English) contrast, /dut/ versus /dyt/, and an English (non-German) contrast, /d epsilon t/ versus /daet/. English and German adults discriminated both contrasts with high levels of accuracy in a categorial AXB task. However, results of an identification and rating task showed that, within each non-native vowel contrast, one vowel perceptually matched a native vowel category better than the other. In experiment 2 discrimination of /dut/ versus /dyt/ and /d epsilon t/ versus /daet/ was examined in English- and German-learning infants in two age groups (6-8 months and 10-12 months) using the conditioned headturn procedure. English and German infants did not differ in their discrimination of either contrast and there were no age differences in discrimination of either contrast for the German or for the English infants. However, in both language groups at both ages, there were clear differences in performance related to the direction in which the vowel change was presented to the infants. For the German contrast, discrimination was significantly poorer when the contrast changed from /dut/ to /dyt/. For the English contrast, discrimination was significantly poorer when the contrast changed from /daet/ to /d epsilon t/. The directional asymmetries observed here and in other infant vowel studies point to a language-universal perceptual pattern which suggests that vowels produced with extreme articulatory postures serve as perceptual attractors in infant vowel perception.