Bidialectal CALD learners of English: Implications on bilingual language disorders and differential diagnosis

Bidialectal learners are found to have better language awareness than monodialectal speakers in their first language (L1). However, few studies have investigated the role of L1 bidialectism in second language (L2) acquisition. Therefore, little is known as to whether error patterns in L2 are caused by learners’ diverse L1 dialectal backgrounds. This study investigates the role of L1 bidialectism on L2, particularly the syntax-semantics interface. Participants were 78 L1-monodialectal (Mandarin) and 79 L1-bidialectal (Mandarin and Wu) English L2 learners. All participants completed a sentence-picture matching task of 40 sentences that were different at the syntax-semantics interface between L1 and L2. The participants performing in the top and bottom 10% were interviewed. The results were both quantitatively and qualitatively analysed. An L1 bidialectal advantage in comprehension at the L2 syntax-semantics interface was found when the interface yields more readings in L2 than in L1. This study provides evidence that L1 bidialectism is an important factor to consider in second language acquisition and speech-language pathology studies. For clinicians, this provides evidence that bidialectism may also impact culturally and linguistically diverse children’s L2 performance and should be considered when making a differential diagnosis between language differences and disorders.