Lexically Guided Perceptual Learning of a Vowel Shift in an Interactive L2 Listening Context

Lexically guided perceptual learning has traditionally been studied with ambiguous consonant sounds to which native listeners are exposed in a purely receptive listening context. To extend previous research, we investigate whether lexically guided learning applies to a vowel shift encountered by non-native listeners in an interactive dialogue. Dutch participants played a two-player game in English in either a control condition, which contained no evidence for a vowel shift, or a lexically constraining condition, in which onscreen lexical information required them to re-interpret their interlocutor's /I/ pronunciations as representing /epsilon/. A phonetic categorization pre-test and post-test were used to assess whether the game shifted listeners' phonemic boundaries such that more of the /epsilon/-/I/ continuum came to be perceived as /epsilon/. Both listener groups showed an overall post-test shift toward /I/, suggesting that vowel perception may be sensitive to directional biases related to properties of the speaker's vowel space. Importantly, listeners in the lexically constraining condition made relatively more post-test /epsilon/ responses than the control group, thereby exhibiting an effect of lexically guided adaptation. The results thus demonstrate that non-native listeners can adjust their phonemic boundaries on the basis of lexical information to accommodate a vowel shift learned in interactive conversation.