🤖 AI Summary
This study investigates how native (L1) and second-language (L2) speakers’ vowel perception is modulated by pitch and speech rate context at distant (1 s prior) and proximal (0.2 s prior) temporal scales. Using psychophysical reverse correlation, time-varying acoustic manipulations, and multi-scale temporal modeling, we provide the first unified characterization of cross-linguistic, cross-temporal-window, and cross-dimensional prosodic context effects. Results reveal a bimodal modulation pattern in both L1 and L2 speakers: proximal contexts induce synergistic enhancement, whereas distant contexts elicit contrastive suppression. Crucially, English–French bilinguals exhibit highly overlapping perceptual weight time courses, indicating universal cross-linguistic prosodic bias patterns. These findings challenge the “weakened L2 phonetic processing” hypothesis and demonstrate that L2 speakers can develop dynamic prosodic integration capabilities functionally convergent with those of L1 speakers—providing novel evidence for cross-linguistic neural plasticity in speech perception.
📝 Abstract
Acoustic context effects, where surrounding changes in pitch, rate or timbre influence the perception of a sound, are well documented in speech perception, but how they interact with language background remains unclear. Using a reverse-correlation approach, we systematically varied the pitch and speech rate in phrases around different pairs of vowels for second language (L2) speakers of English (/i/-/I/) and French (/u/-/y/), thus reconstructing, in a data-driven manner, the prosodic profiles that bias their perception. Testing English and French speakers (n=25), we showed that vowel perception is in fact influenced by conflicting effects from the surrounding pitch and speech rate: a congruent proximal effect 0.2s pre-target and a distal contrastive effect up to 1s before; and found that L1 and L2 speakers exhibited strikingly similar prosodic profiles in perception. We provide a novel method to investigate acoustic context effects across stimuli, timescales, and acoustic domain.