Flexibility and evolution of cue weighting after a tonal split: an experimental field study on Tamang

Abstract

Abstract We conducted a perception experiment in the field to examine the synchronic consequences of a tonal split in Risiangku Tamang (Tibeto-Burman). Proto-Tamang was a two-tone language with three series of plosives and two series of continuants. The merger of its continuants provoked a split of the original two tones into four, two high and two low, which combine pitch and phonation features. The quasi-merger of the voiced and voiceless plosives left sporadic remnants of initial plosive voicing in low tone syllables. A previous production study has shown that speakers use pitch and phonation features concomitantly to distinguish high from low tones, while producing initial plosive voicing only marginally with low tones. The present perception study establishes the preeminence of the pitch cue, but also confirms the effective use of the two older cues in tone identification. An apparent-time analysis shows the phonation cue to be less used by younger speakers, in keeping with the historical evolution. The use of the residual voicing of plosives, instead of decreasing with younger speakers, is shown to increase. This result could be explained by an increased contact of the young generation with Nepali, a toneless Indo-Aryan language with a four-way initial plosive contrast.