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Introduction: Lateral temporal neural measures (Na and T-complex Ta and Tb) of the auditory evoked potential (AEP) index auditory/speech processing and have been observed in children and adults. While Na is already present in children under 4 years of age, Ta emerges from 4 years of age, and Tb appears even later. The T-complex has been found to be sensitive to language experience in Spanish-English and Turkish-German children and adults. In particular, Ta elicited to a vowel has been found to be sensitive to language experience in bilingual preschool children. This paper examines neural responses in 4-to-6-year-old Italian-German bilingual and German monolingual children using language-specific phonetic cues for voicing. Methods: We tested children's processing of voicing features in bilabial stop consonants in relation to (1) their language status (i.e., being monolingual vs. bilingual) as well as to (2) their relative amount of current exposure to the heritage (Italian) and the societal language (German). Italian-German bilingual and German monolingual children were hypothesized to encode the temporal properties of a set of Voice Onset Time (VOT) stimuli differently as indexed by Ta and Tb. Results: The results revealed no main effects of language group, but interactions of group with hemisphere and stimulus. In particular, bilingual children showed less hemispheric differentiation and an attenuated (less positive) response at the right site (T8) for the 0 ms VOT stimulus during the Ta-Tb time window. Children with more German (and consequently, less Italian) input showed a more positive T8 response for the Na, Ta and Tb time intervals. Discussion: These findings partially replicated previous studies, but also revealed that stimulus factors modulate the response. They suggest that a delay in commitment is found only in bilinguals with less input in the target language, and those who are strongly dominant in one of the two languages will resemble monolinguals in the development of T-complex responses. However, the finding of greater Na positivity for German-dominant bilinguals suggests that their specific experience also influences processing, but perhaps via a different mechanism than found for the more balanced bilinguals. [ABSTRACT FROM AUTHOR]

Many studies have shown that input in more than one language influences children's phonemic development. In this study, we examined the neural processes supporting perception of Voice Onset Time (VOT) in bilingual Italian-German children and their monolingual German peers. While German contrasts short-lag and long-lag, Italian contrasts short-lag and voicing lead. We examined whether bilinguals' phonetic/phonological systems for the two languages develop independently or whether they influence each other, and what role language input plays in the formation of phonetic/phonological categories. Forty five-year-old children (16 monolingual German, 24 bilingual Italian-German) were tested in an oddball design expected to elicit a neural Mismatch Response (MMR). The stimuli were bilabial stop VOT contrasts with the short-lag stop, common to both languages, as the standard. Four deviant VOTs were selected: 92 ms and 36 ms lag for German; 112 ms and 36 ms voicing lead for Italian. Bilingual children's language background was assessed using a caregiver questionnaire. Italian-German bilingual 5-year-old children and German monolingual controls showed similar MMRs to German long-lag and Italian voicing lead VOT, except for the 36 ms long-lag deviant; this acoustically difficult distinction did not elicit a robust negative MMR in the bilingual children. The lack of a difference between the bilinguals and monolinguals for voicing lead suggests that the amount of input in Italian for the bilinguals was not sufficient to lead to an advantage compared to the monolingual German children. Alternatively, the finding could indicate that voicing lead is easier to discriminate than voicing lag. [ABSTRACT FROM AUTHOR]