The voice of experience: Causal inference in phonotactic adaptation

Successfully grappling with widespread linguistic variation requires listeners to adapt to systematic variation in the environment while discarding incidental variation, based on listeners’ prior experience. We examine the role of prior experience in phonotactic learning. Talkers who differ in their language background are more likely to vary in their phonotactic grammars than talkers who share a language variety. This predicts stronger adaptation to novel phonotactics when listeners are exposed to multiple talkers from different versus shared language backgrounds. We tested this by exposing listeners to two talkers, each of whom exhibited a different phonotactic constraint, in a recognition memory task. In Experiment 1, English listeners exposed to talkers differing in language background (English versus French) showed a greater degree of adaptation relative to cases where the talkers shared a language background (English or French). Experiment 2 found similar results when English listeners were exposed to talkers from different, non-native language backgrounds (Hindi versus Hungarian), suggesting that listeners make fine-grained distinctions between different non-native language phonotactics. These results suggest that phonotactic adaptation is flexible, but constrained by the fine-grained causal inferences listeners draw from their prior experience.