Iu Mien Tone Change in Real Time: A Restudy Of L-Thongkum (1988)

Abstract

This study investigates tone changes in Iu Mien, a Hmong-Mien language with two complex contour tones: high rising-falling (T3) and low rising-falling (T4). L-Thongkum (1988) observed younger speakers producing rising variants of T3 and T4, which she attributed to Thai contact. This study replicates L-Thongkum’s study 34 years later to observe tone changes in real time and examine the potential role of peak delay, a phonetic bias resulting in a later f0 peak. 40 speakers (ages 12-84) produced T3 and T4 monosyllables in isolation and in a carrier phrase. f0 was modeled using Generalized Additive Mixed Modeling (GAMM). Results confirm incremental change toward rising variants of T3 and T4. Older speakers showed peak delay (with more of a rising contour) under conditions of shorter duration and preceding low tone. Critically, younger speakers produced peak-delayed, rising variants in all conditions, indicating generalization of the rising contour. While language contact may have initiated the changes, a phonetic bias toward peak delay generated the seeds of potential change. The change from rising-falling > rising aligns with apparent-time studies in other Asian languages, suggesting this may be a crosslinguistically unidirectional pathway.