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had been replaced by an ambiguous sound.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).