An integrated tone box scheme for determining tones in Tai varieties beyond Southwestern Tai: diachronic and synchronic concerns

Abstract When applied to Tai varieties beyond Southwestern Tai, Gedney’s tone box framework and its revised versions have several shortcomings, the most notable of which is the lack of consideration of diachronic issues that give rise to more complicated tonal correspondences. This paper proposes a more widely applicable Tai tone box chart with one additional tier based on the more probable tone-conditioning phonetic nature of onsets found in non-Southwestern Tai varieties. This Tai tone box chart has been designed to be paired with an ancillary chart to explain the essential diachronic processes of different Tai varieties. It thus provides insights into the revision of Proto-Tai phonological reconstructions based on tonology and support for the early-stage Southern-Northern Tai division and the Southwestern-Central Tai versus Yongnan Zhuang-Saek-Northern Zhuang divisions.