The present study deals with the perception (identification and discrimination) of an English phonemic contrast (/t∫/–/∫/, as in cheat and sheet) by speakers of two Mexican varieties of Spanish who are learning English as a foreign language. Unlike English, Spanish does not contrast /t∫/ and /∫/ phonemically. Most Spanish varieties have [t∫], but not [∫]. In northwestern Mexico, [∫] and [t∫] find themselves in a situation of “free” variation—perhaps conditioned, to some extent, by social factors, but not in complementary distribution. In this variety, [∫] and [t∫] are variants of the same phoneme. The present study compares the perceptual behavior of English learners from northwestern Mexico, with that of learners from central Mexico, whose native dialect includes only [t∫]. The results of a word-categorization task show that both groups of learners find cheat and sheet difficult to identify in the context of each other, but that, relative to the other learner group, the group of learners in northwestern Mexico find this task to be particularly challenging. The results of a categorical discrimination task show that both learner groups find the members of the /t∫/–/∫/ contrast difficult to discriminate. On average, accuracy is lower for the group of learners in northwestern Mexico than it is for the central Mexicans. The findings suggest that the phonetic variants found in one’s native dialect modulate the perception of nonnative sounds and, consequently, that people who speak different regional varieties of the same language may face different obstacles when learning the sounds of their second language.

This study investigates the auditory lexical processing of the two main variants of “ch” (as in charco ‘puddle’) used in the Spanish spoken in northwestern Mexico. A feature of this dialect is the variable implementation of “ch” either as an affricate, [tʃ], or a fricative, [ʃ]. We designed an auditory lexical decision task with auditory priming to explore the effects (if any) of this variability on the recognition of words by members of this community. Target words were presented with either variant as their word-initial consonant (e.g., [tʃ]arco ~ [ʃ]arco), and they were preceded by auditory primes with a matching variant ([tʃ]arco-[tʃ]arco, [ʃ]arco-[ʃ]arco), a mismatching variant ([tʃ]arco-[ʃ]arco, [ʃ]arco-[tʃ]arco), or an unrelated prime. The results show that members of this community are equally likely to accept Spanish word forms produced with either variant. Furthermore, both variants primed listeners equally effectively in their recognition of spoken words, suggesting that both activate the same entry in their mental lexicon (as opposed to parallel representations). Finally, recognition was found to be faster when the word-initial phonetic variant was [tʃ]; this suggests a privilege of [tʃ] over [ʃ] at some level of representation. The results support the claim that, in cases of sociophonetic variability, members of the speech community may include more than one phonetic variant in their mental representation of words, but that, even in such cases, one of the variants may take processing precedence over the other. These results, in turn, suggest it is possible that the nature of the mental representations of an individual are particularly affected by the dialect spoken in their speech community.