Past research has established that listeners can accommodate a wide range of talkers in understanding language. How this adjustment operates, however, is a matter of debate. Here, listeners were exposed to spoken words from a speaker of an American English dialect in which the vowel /ae/ is raised before /g/, but not before /k/. Results from two experiments showed that listeners' identification of /k/-final words like "back" (which are unaffected by the dialect) was facilitated by prior exposure to their dialect-affected /g/-final counterparts, e.g., "bag". This facilitation occurred because the competition between interpretations, e.g., "bag" or "back", while hearing the initial portion of the input [bae], was mitigated by the reduced probability for the input to correspond to "bag" as produced by this talker. Thus, adaptation to an accent is not just a matter of adjusting the speech signal as it is being heard; adaptation involves dynamic adjustment of the representations stored in the lexicon, according to the characteristics of the speaker or the context. (Contains 3 figures.)