Questioning monolingualism

While previous research has extensively investigated how multilingual experience shapes linguistic and cognitive processing, much of this work has overlooked bidialectal speakers – individuals who navigate multiple linguistic systems within the same language. By treating bidialectal speakers as monolinguals, prior studies may have mischaracterized the nature of native language representation and processing, particularly in languages like Chinese, where bidialectalism is widespread. This dissertation examines the impact of bidialectal experience on speech production, perception, and language control, drawing parallels between bidialectal and bilingual processing while identifying nuanced distinctions between the two. This dissertation argues that bidialectalism constitutes a unique form of linguistic experience that requires greater integration into psycholinguistic models of multilingualism.The empirical studies presented in this dissertation investigated these questions from three experimental approaches. Chapter II examines the influence of using a second dialect on native tone production in Chengdu Mandarin-Standard Mandarin bidialectal speakers. The results reveal that the use of Standard Mandarin influences Chengdu Mandarin tone production. Bidialectal speakers who use Standard Mandarin more frequently exhibit dissimilatory drift in Chengdu Mandarin tones that are perceptually linked across the dialects and reduced within-dialect tonal contrast in Chengdu Mandarin tones without a clear Standard Mandarin counterpart. These findings are consistent with previous studies in bilingual production and align with bilingual speech learning models, suggesting that bidialectal speakers develop a shared phonetic space for both dialects.