Although pre-low raising (PLR) is an extensively studied contextual tonal variation, its underlying mechanism is barely understood. This paper explores the effect of duration on PLR in Cantonese and Thai, and examines how speech rate and vowel quantity interact with its realization in these languages respectively. Results for Cantonese revealed that PLR always occurred before a large falling excursion (i.e. T1T4); in other tonal contexts, it was observed more often in faster speech. In the Thai corpus, although PLR also occurred before large falling excursions, vowel quantity did not appear to influence its realization. These results are discussed in terms of possible accounts of the underlying mechanism of PLR.

ライマンの法則や語彙層など連濁についてさまざまな特性が議論されてきた。この講演では，Tamaoka, Ihara, Murata & Lim (2009, Journal of Japanese Linguistics)，Tamaoka & Ikeda (2010, 言語研究)およびTamaoka, Hayakawa & Vance (2016, Journal of Japanese Linguistics)で展開されている連濁の諸特性に関する検証を，統計手法を詳細に解説しながら紹介する。