Learning a talker or learning an accent: Acoustic similarity constrains generalization of foreign accent adaptation to new talkers

- Listeners generalize phonetic retuning across talkers of the same foreign accent.
- Generalization results in reduced lexical competition for words from a novel talker.
- Multiple talker exposure is not necessary to elicit talker-independent learning.
- Bottom-up acoustic similarity between talkers modulates talker generalization.

Past research has revealed that native listeners use top-down information to adjust the mapping from speech sounds to phonetic categories. Such phonetic adjustments help listeners adapt to foreign-accented speech. However, the mechanism by which talker-specific adaptation generalizes to other talkers is poorly understood. Here we asked what conditions induce cross-talker generalization in talker accent adaptation. Native-English listeners were exposed to Mandarin-accented words, produced by a single talker or multiple talkers. Following exposure, adaptation to the accent was tested by recognition of novel words in a task that assesses online lexical access. Crucially, test words were novel words and were produced by a novel Mandarin-accented talker. Results indicated that regardless of exposure condition (single or multiple talker exposure), generalization was greatest when the talkers were acoustically similar to one another, suggesting that listeners were not developing an accent-wide schema for Mandarin talkers, but rather attuning to the specific acoustic-phonetic properties of the talkers. Implications for general mechanisms of talker generalization in speech adaptation are discussed.