Unmerging the sibilant merger via phonetic imitation: Phonetic, phonological, and social factors

This study explores the ways in which marginal contrasts are clearly realized by merged speakers as a result of exposure to a distinct speaker. The alveolar-retroflex sibilants in Taiwan Mandarin (TM) were chosen as a test case as the distinction is variably implemented, ranging from a complete merger to clear contrasts. In a spontaneous phonetic imitation task, merged and distinct TM speakers imitated the speech of a distinct model talker of Mainland Mandarin. The results show that merged speakers substantially increased the spectral distance between the two sibilants during imitation, essentially reversing the merger. Specific patterns of the merger reversal were further enriched by phonetic and social factors. The categories were unmerged by making reference to each individual's phonetic space; speakers with higher baseline spectral frequencies restored the underlying retroflex category, and those with lower baselines retrieved the alveolars through dentalization. Furthermore, the merger reversal showed preferential convergence conditioned by gender—female speakers were less willing to accommodate socially undesirable strong retroflexion. Taken together, phonetic imitation reflected speakers’ abstract phonological knowledge, but specific patterns were also shaped by a careful calibration of phonetic space and the desired phonetic norms of the speech community.