Existing studies have suggested that there may be a link between perception and production of speech sounds. In this paper we examine this link using data collected on Singapore English-Mandarin bilingual adults. We used a 2AFC task to measure perception of the Singapore Mandarin [tsʰuə́n]-[ʈʂʰuə́n] alveolar-retroflex contrast, and measured production using centre of gravity (CoG) measurements on speech recordings of alveolar and retroflex words. We found that a perception-production link may exist in our participants, with participants who exhibit less retroflexion in speech showing less sensitivity to retroflexion in ambiguous speech sounds.

Bilinguals are reported to have language learning advantages. One possible pathway is a language-specific transfer effect, whereby sensitivity to structural regularities in known languages can be brought to novel languages that share features. To test for specific linguistic feature transfer, we designed a task for bilinguals with homogeneous language exposure (bilingual in same languages) and heterogeneous feature representation (differing proficiencies). As Hindi and Mandarin have retroflexion in phoneme contrasts, we conducted a pre-registered study with a statistical learning task of a Hindi dental-retroflex contrast on parallel English-Mandarin bilinguals with varied Mandarin proficiency. Unlike the pilot study (N = 15), the main study (N = 50) found no evidence for a learning effect, and language-experience did not explain learning variance. As these stimuli have shown learning effects in children, learning effects for this feature may be fragile in this adult population, and language-specific neural commitments may prevent learning of the contrast.

Chinese phonology features a contrast between alveolar and retroflex places of articulation, particularly in the standard Beijing variety of Mandarin. However, studies have shown that ‘outer-circle’ varieties (such as in Taiwan and Singapore) have a less clear contrast, termed “deretroflexion”, which results in poor contrastive perception for Taiwan Mandarin speakers. However, our previous study did not find this deficit in Singapore Mandarin speakers. In this preregistered follow-up study, we investigate how Singapore Mandarin speakers perceive the alveolar-retroflex contrast and examine if differences in perception are linked to Mandarin understanding proficiency. Our results (N = 62) reveal that while Singapore Mandarin speakers perceive an alveolar-retroflex phoneme contrast, there is a wide range of differences in ambiguity resolution across the alveolar-retroflex acoustic spectrum. We did not find a link between perceptual differences and Mandarin understanding proficiency, indicating that highly ‘tuned’ perceptual sensitivity is not needed for high Mandarin understanding proficiency.

Language-specific accounts of bilingual learning advantages suggest that advantages in language learning are tied to an individual's linguistic experience, with learning advantages stemming from transfer effects between known and to-be-learnt language features. To test this hypothesis, we trained Singapore English-Mandarin bilinguals on a synthesised alveolar-retroflex [ts ∞u…ôÃÅn]-[ à Ç ∞u…ôÃÅn] contrast with a bimodal distributional learning paradigm. We reasoned that participants with higher Mandarin understanding proficiencies would show larger distributional learning effects due to transfer between real-world Mandarin experience and the training stimuli. We examined overall learning effects in a pilot study (N = 20) and a preregistered main study (N = 50). We found evidence of learning in both the pilot and the main study. We also found evidence of a transfer effect tied to individual Mandarin skills, with larger learning effects linked to higher Mandarin understanding proficiencies. This study demonstrates specific advantages of language background on perceptual learning at the individual level.