Testing the Obligatory Contour Principle and Tonal Markedness Scale effects in L2 tonal acquisition

What makes Mandarin tones challenging for second language (L2) learners? Several recent studies suggest that two phonological universals, the Obligatory Contour Principle and the Tonal Markedness Scale, may constrain L2 tonal acquisition, regardless of learners' first language. We assessed the role of these universals in the L2 acquisition of Mandarin tones with a perceptual testing protocol that implemented a number of methodological improvements over previous studies. Bayesian mixed-effects analyses supported the null effects of both universals. Instead, a clear determinant of tonal identification accuracy was participants’ pitch discrimination ability. We explain the discrepancy between prior research and the current findings in terms of the representational levels that are targeted by perceptual and production tasks. All materials, data, and code are publicly available in the OSF repository at https://osf.io/ezadw/.