The flexibility of human speech recognition and the seeds of language change

ANNE CUTLER, Max Planck Institute for Psycholinguistics

Phonetic categories of the mother tongue are learned early, and are notoriously well-anchored, in the sense that they can interfere with speech perception in second languages. However, phonetic categories of the mother tongue are not immutable. Category boundaries change over time within language communities and within individuals. A series of experiments (beginning with Norris, McQueen & Cutler, Cog. Psych., 2003) has explored the factors which determine how adult listeners retune phonetic contrasts. Dutch subjects made lexical decisions on words and nonwords, where a final phoneme in some words had been replaced by an ambiguous sound. This experience led them to shift their category boundary for a subsequent phonetic categorisation task. The boundary shift only occurred when lexical information was available to train the categorisation; exposure to the ambiguous sound in nonwords did not induce retuning. Explicit attention to the lexical information is, however, not required. Retuning can be initially speaker-specific and thus enables adjustment for individual speakers without affecting perception of other speakers. Finally, retuning generalises across words. These results suggest that feedback links in speech perception are used for learning but not for online processing, and they further argue against speech perception models with no abstract prelexical or lexical representations (such as radical episodic models).