L3 acquisition of Mandarin Chinese stop consonants by learners with L1 Spanish/Thai and L2 English

This study examines the source of cross-linguistic influence (CLI) in the L3 phonological acquisition of Mandarin Chinese stop consonants. We compared Voice Onset Time (VOT) production in two groups of multilinguals: L1 Spanish learners (a ``true voicing'' language) and L1 Thai learners (a three-way contrast language), both with English as an L2. Results indicate that the typological similarity between L1 and L3, rather than L2 status, determines L3 production outcomes. L1 Thai learners successfully mapped Mandarin stops to their native (un)aspirated categories, achieving near-native accuracy via facilitative transfer. In contrast, L1 Spanish learners showed non-facilitative CLI from their L1. We further identify regressive transfer (phonetic drift) exclusively in the Spanish group, where exposure to aspiration systems (English and Mandarin) shifted native Spanish voiceless stops away from the monolingual baseline. These findings challenge the L2 Status Factor, suggesting that in the absence of high L2 proficiency or dominant societal use, the L1 remains the primary source of CLI for L3 phonological acquisition.