Electrophysiological Correlates of Phonological Processing: A Cross-linguistic Study G. Dehaene-Lambertz CNRS UMR 8554 and EHESS, Paris, France and Centre Hospitalier Universitaire Bicetre, France E. Dupoux and A. Gout CNRS UMR 8554 and EHESS, Paris, France Abstract & It is well known that speech perception is deeply affected by the phoneme categories of the native language. Recent studies have found that phonotactics, i.e., constraints on the cooccurrence of phonemes within words, also have a considerable impact on speech perception routines. For example, Japanese does not allow (nonnasal) coda consonants. When presented with stimuli that violate this constraint, as in / ebzo/, Japanese adults report that they hear a /u/ between consonants, i.e., /ebuzo/. We examine this phenomenon using event-related potentials (ERPs) on French and Japanese participants in order to study how and when the phonotactic properties of the native language affect speech perception routines. Trials using four similar precursor stimuli were presented followed by a test stimulus that was either identical or different depending on the presence or absence of an epenthetic vowel /u/ between two consonants (e.g., ‘‘ebuzo ebuzo ebuzo — ebzo’’). Behavioral results confirm that Japa- nese, unlike French participants, are not able to discriminate between identical and deviant trials. In ERPs, three mismatch responses were recorded in French participants. These responses were either absent or significantly weaker for Japanese. In particular, a component similar in latency and topography to the mismatch negativity (MMN) was recorded for French, but not for Japanese participants. Our results suggest that the impact of phonotactics takes place early in speech processing and support models of speech perception, which postulate that the input signal is directly parsed into the native language phonological format. We speculate that such a fast computation of a phonological representation should facilitate lexical access, especially in degraded conditions. & INTRODUCTION Humans use complex sounds to communicate and convey meaning. The way in which the mapping between the signal and the concepts is realized, how- ever, is heavily language dependent. For instance, some languages use only six consonants to construct words, others more than 80. Some use three vowels, others more than 20. The particular phoneme inven- tory of the native language has a strong influence on speech discrimination capacities in adults. For in- stance, adult monolinguals in Japanese have a lot of trouble in distinguishing English /r/ from /l/ sounds, because both are perceived as a single /R/. However, language sound systems differ in ways other than the repertoire of phonemes. They also differ in how particular phonemes can combine in a sequence, i.e., its phonotactic properties. In Japanese, only a rather strict alternation of vowels and consonants is allowed, whereas English allows for clusters of several conso- nants (e.g., strengths). A lot of research has been devoted to the effect of the phoneme inventory on speech perception, but the role played by the higher- order properties of linguistic signals is only starting to be explored. The focus of this paper is to study, using event-related potentials (ERPs) methodology and a cross-linguistic design, whether phonotactic properties have effects on speech perception routines that are as profound as those triggered by differences in pho- neme inventories. The acquisition of the language phoneme inventory is very quick. At 6 months, infants have established prototypes for the vowels used in their language (Kuhl, Williams, Lacerda, Stevens, & Lindblom, 1992) and start to loose sensitivity to nonnative vowels (Polka & Wer- ker, 1994). At 12 months, they loose the capacity to discriminate nonnative consonantal contrasts, or at least those that can be assimilated to native categories (Best, McRoberts, & Sithole, 1988; Werker & Tees, 1984). After that, the capacity to perceive foreign phonetic contrasts seems remarkably stable and poor, © 2000 Massachusetts Institute of Technology Journal of Cognitive Neuroscience 12:4, pp. 635–647