The Influence of Tonal and Atonal Bilingualism on Children's Lexical and Non-Lexical Tone Perception.

This study examined how bilingualism in an atonal language, in addition to a tonal language, influences lexical and non-lexical tone perception and word learning during childhood. Forty children aged 5;3-7;2, bilingual either in English and Mandarin or English and another atonal language, were tested on Mandarin lexical tone discrimination, level-pitch sine-wave tone discrimination, and learning of novel words differing minimally in Mandarin lexical tone. Mandarin-English bilingual children discriminated between and learned novel words differing minimally in Mandarin lexical tone more accurately than their atonal-English bilingual peers. However, Mandarin-English and atonal-English bilingual children discriminated between level-pitch sine-wave tones with similar accuracy. Moreover, atonal-English bilingual children showed a tendency to perceive differing Mandarin lexical and level-pitch sine-wave tones as identical, whereas their Mandarin-English peers showed no such tendency. These results indicate that bilingualism in a tonal language in addition to an atonal language-but not bilingualism in two atonal languages-allows for continued sensitivity to lexical tone beyond infancy. Moreover, they suggest that although tonal-atonal bilingualism does not enhance sensitivity to differences in pitch between sine-wave tones beyond infancy any more effectively than atonal-atonal bilingualism, it protects against the development of biases to perceive differing lexical and non-lexical tones as identical. Together, the results indicate that, beyond infancy, tonal-atonal bilinguals process lexical tones using different cognitive mechanisms than atonal-atonal bilinguals, but that both groups process level-pitch non-lexical tone using the same cognitive mechanisms.