Can bilingual children turn one language off? Evidence from perceptual switching

Language selective or non-selective in bilingual lexical access? It depends on lexical tones!

Much of the literature surrounding bilingual spoken word recognition is based on bilinguals of non-tonal languages. In the Mandarin spoken word recognition literature, lexical tones are often considered as equally important as segments in lexical processing. It is unclear whether and how lexical tones contribute to bilingual language processing. One recent study demonstrates that tonal bilinguals require the availability of both tonal and segmental information to induce cross-language lexical competition during bilingual lexical access, even without phonological overlap between the target and non-target language. The current study investigates whether overt phonological overlap between the target and non-target language would equally require both tonal and segmental information available to induce cross-language lexical competition. We employed two auditory lexical decision experiments with both Mandarin-English bilinguals and English monolinguals to test whether inter-lingual homophones (IH) would induce lexical competition from the non-target language, L1 Mandarin. Our results show that cross-language lexical competition was only observed with the presence of lexical tones, in addition to segmental overlap.

How bilinguals perceive speech depends on which language they think they're hearing

Bilinguals understand when the communication context calls for speaking a particular language and can switch from speaking one language to speaking the other based on such conceptual knowledge. There is disagreement regarding whether conceptually-based language selection is also possible in the listening modality. For example, can bilingual listeners perceptually adjust to changes in pronunciation across languages based on their conceptual understanding of which language they're currently hearing? We asked French- and Spanish-English bilinguals to identify nonsense monosyllables as beginning with /b/ or /p/, speech categories that French and Spanish speakers pronounce differently than English speakers. We conceptually cued each bilingual group to one of their two languages or the other by explicitly instructing them that the speech items were word onsets in that language, uttered by a native speaker thereof. Both groups adjusted their /b-p/ identification boundary as a function of this conceptual cue to the language context. These results support a bilingual model permitting conceptually-based language selection on both the speaking and listening end of a communicative exchange.

What Can Lexical Tone Training Studies in Adults Tell Us about Tone Processing in Children?

A growing number of studies on the acquisition of lexical tone by adult learners have revealed that factors such as language background, musical experience, cognitive abilities, and neuroanatomy all play a role in determining tone learning success. On the basis of these findings, it has been argued that the effectiveness of tone learning in adulthood depends on individual differences in these factors. However, it is not clear whether similar individual differences play an analogous role in tone learning in childhood. Indeed, relatively few studies have made comparisons between how adults and children learn lexical tones. Here, we review recent developments for tone learning in both adults and children. The review covers tone training in a range of contexts, including in naive listeners, in native speakers of other tone languages, in listeners with varying levels of musical experience, and in individuals with speech and hearing disorders. Finally, we discuss the parallels between adult and child tone learning, and provide recommendations concerning how findings in adult tone training can provide insights into tone learning for children by accommodating the needs of individual learners.

How Native Prosody Affects Pitch Processing during Word Learning in Limburgian and Dutch Toddlers and Adults

In this study, Limburgian and Dutch 2.5- to 4-year-olds and adults took part in a word learning experiment. Following the procedure employed by Quam and Swingley (2010) and Singh et al. (2014), participants learned two novel word-object mappings. After training, word recognition was tested in correct pronunciation (CP) trials and mispronunciation (MP) trials featuring a pitch change. Since Limburgian is considered a restricted tone language, we expected that the pitch change would hinder word recognition in Limburgian, but not in non-tonal Dutch listeners. Contrary to our expectations, both Limburgian and Dutch children appeared to be sensitive to pitch changes in newly learned words, indicated by a significant decrease in target fixation in MP trials compared to CP trials. Limburgian and Dutch adults showed very strong naming effects in both trial types. The results are discussed against the background of the influence of the native prosodic system.

Tone Attrition in Mandarin Speakers of Varying English Proficiency

PURPOSE

The purpose of this study was to determine whether the degree of dominance of Mandarin-English bilinguals' languages affects phonetic processing of tone content in their native language, Mandarin.

METHOD

We tested 72 Mandarin-English bilingual college students with a range of language-dominance profiles in the 2 languages and ages of acquisition of English. Participants viewed 2 photographs at a time while hearing a familiar Mandarin word referring to 1 photograph. The names of the 2 photographs diverged in tone, vowels, or both. Word recognition was evaluated using clicking accuracy, reaction times, and an online recognition measure (gaze) and was compared in the 3 conditions.

RESULTS

Relative proficiency in English was correlated with reduced word recognition success in tone-disambiguated trials, but not in vowel-disambiguated trials, across all 3 dependent measures. This selective attrition for tone content emerged even though all bilinguals had learned Mandarin from birth. Lengthy experience with English thus weakened tone use.

CONCLUSIONS

This finding has implications for the question of the extent to which bilinguals' 2 phonetic systems interact. It suggests that bilinguals may not process pitch information language-specifically and that processing strategies from the dominant language may affect phonetic processing in the nondominant language-even when the latter was learned natively.

Mandarin-English Bilinguals Process Lexical Tones in Newly Learned Words in Accordance with the Language Context

Previous research has mainly considered the impact of tone-language experience on ability to discriminate linguistic pitch, but proficient bilingual listening requires differential processing of sound variation in each language context. Here, we ask whether Mandarin-English bilinguals, for whom pitch indicates word distinctions in one language but not the other, can process pitch differently in a Mandarin context vs. an English context. Across three eye-tracked word-learning experiments, results indicated that tone-intonation bilinguals process tone in accordance with the language context. In Experiment 1, 51 Mandarin-English bilinguals and 26 English speakers without tone experience were taught Mandarin-compatible novel words with tones. Mandarin-English bilinguals out-performed English speakers, and, for bilinguals, overall accuracy was correlated with Mandarin dominance. Experiment 2 taught 24 Mandarin-English bilinguals and 25 English speakers novel words with Mandarin-like tones, but English-like phonemes and phonotactics. The Mandarin-dominance advantages observed in Experiment 1 disappeared when words were English-like. Experiment 3 contrasted Mandarin-like vs. English-like words in a within-subjects design, providing even stronger evidence that bilinguals can process tone language-specifically. Bilinguals (N = 58), regardless of language dominance, attended more to tone than English speakers without Mandarin experience (N = 28), but only when words were Mandarin-like-not when they were English-like. Mandarin-English bilinguals thus tailor tone processing to the within-word language context.

Limits on Monolingualism? A Comparison of Monolingual and Bilingual Infants' Abilities to Integrate Lexical Tone in Novel Word Learning

To construct their first lexicon, infants must determine the relationship between native phonological variation and the meanings of words. This process is arguably more complex for bilingual learners who are often confronted with phonological conflict: phonological variation that is lexically relevant in one language may be lexically irrelevant in the other. In a series of four experiments, the present study investigated English-Mandarin bilingual infants' abilities to negotiate phonological conflict introduced by learning both a tone and a non-tone language. In a novel word learning task, bilingual children were tested on their sensitivity to tone variation in English and Mandarin contexts. Their abilities to interpret tone variation in a language-dependent manner were compared to those of monolingual Mandarin learning infants. Results demonstrated that at 12-13 months, bilingual infants demonstrated the ability to bind tone to word meanings in Mandarin, but to disregard tone variation when learning new words in English. In contrast, monolingual learners of Mandarin did not show evidence of integrating tones into word meanings in Mandarin at the same age even though they were learning a tone language. However, a tone discrimination paradigm confirmed that monolingual Mandarin learning infants were able to tell these tones apart at 12-13 months under a different set of conditions. Later, at 17-18 months, monolingual Mandarin learners were able to bind tone variation to word meanings when learning new words. Our findings are discussed in terms of cognitive adaptations associated with bilingualism that may ease the negotiation of phonological conflict and facilitate precocious uptake of certain properties of each language.