
Mutual intelligibility of dialects is not completely predicted by genetic relationships.

Additionally, three dialects have low mutual intelligibility. The results show that Sui has four main dialects and that one of these is genetically more closely affiliated to Kam than to Sui. The report also includes wordlist data, phonology sketches for each data point, and interlinearised RTT texts. Finally, it describes and discusses RTT methodology and results. Thirdly, it applies Levenshtein distance analysis to the data and describes the resulting dialect groups. Secondly, it maps out dialect groups based on synchronic lexical similarity. Based on the primary data and on Thurgood’s (1988) Proto-Kam-Sui, and drawing on related languages as well as various other reconstructions, this work first charts the historical development of the Sui dialects. Comprehension of four Sui dialects was also tested across the region using Recorded Text Tests (RTTs). A 600-item wordlist was collected from sixteen data points. The goals of the survey were to document the Sui dialect situation and to elucidate the genetic and synchronic relationships among the various dialects. This research presents the results of a large-scale survey of the Sui language. The Sui language belongs to the Kam-Sui branch of the Tai-Kadai language family. (Edited by Andy Castro and Pan Xingwen) The Sui are an official minority group of China with a population of around 430,000. It is hoped that this thesis will serve as a synthesis of the WK research that has gone on up to this point and provide a starting point for the further investigation of WK languages. While intra-Bru isoglosses were discovered, no indications were found of sub-groupings within the Bru language community and the entire Bru area remains best described as a dialect continuum. This makes sense based on the geographic isolation of the western Kuay languages (Suay) of Laos. An analysis of the phonological isoglosses discovered here reveals that the Kuay sub-group may be further divisible into an eastern branch and a western branch.

No significant consonant changes were found between PK and PWK, though the process of initial stop devoicing likely did begin in the PWK period or slightly after under Middle Khmer influence. This precludes the possibility of PWK and PKuay being marked by register contrast.

No register split is reconstructed for PWK vocalism on account of the transitional, pre-register vocalism described for modern Suay (Ferlus 1971). This thesis presents an exploration of the historical phonology of the West Katuic language family ( PWK *ɔɔ, which caused the lowering of PK *ɔɔ > PWK *ɒɒ.
