Fundamental questions concerning language learning remain unanswered. Some foreign learners are able to acquire a foreign language very successfully, whereas others are frustrated by their lack of progress. It is not clear why some learners flourish while others in the same setting struggle. Our study, published in Bilingualism: Language and Cognition sought to shed some light on this topic.
Numerous factors are thought to be advantageous for non-native language learning although they are typically investigated in isolation, and the interaction between them is not understood. Firstly, it is often claimed that it is easier for bilinguals to acquire a third language than it is for monolinguals to acquire a second. This may be due to cognitive advantages associated with bilingualism, knowledge of a greater number of phonetic features, or greater perceptual flexibility that comes from having already learned an additional language. Secondly, closely related languages may be easier to learn because learners may benefit from their existing knowledge and fast-track their learning. Closely related languages are likely to share common features, and may thus allow a learner to skip having to learn those features. Thirdly, anecdotal evidence suggests that certain phonetic features (and perhaps even certain languages, more generally) might be universally more difficult to acquire regardless of prior language experience.
We tested each of these hypotheses in a series of experiments in which adults learned several artificial languages with vocabularies that differentiated words using foreign phonetic contrasts. In the first experiment, Mandarin–English bilinguals outlearned English monolinguals for both Mandarin-like and English-like languages, and both groups found the Mandarin-like (retroflex) artificial language easier to learn than the English-like (fricative voicing). In the second experiment, bilinguals again outlearned English monolinguals for the Mandarin-like artificial language. However, only Korean–English bilinguals showed an advantage over monolinguals for the more difficult Korean-like (lenition) language. Thus it seems that bilinguals, relative to monolinguals, show a general advantage when learning ‘easy’ phonetic contrasts, but similarity to the native language is useful for learning universally ‘difficult’ contrasts. These findings raise interesting new questions that we are pursuing in subsequent language learning experiments concerning the interaction between the characteristics of the language to be learned and individual differences among learners.