Abstract:
The research aims at locating the dialect boundary between eastern southern Thai and western southern Thai on the basis of variation between /k/ and /?/ in the final position of long syllables. Based on a survey of related literature it was hypothesized that the dialect boundary should be found in the following 5, low-land areas : 1.between Amphoe Muang and Amphoe Kanchanadit in Surat Thani. 2.between Amphoe Nabon and Amphoe Lan Saka in Nakhon Si Thammarat. 3.between Amphoe Thung Song and Amphoe Ron Phibun in Nakhon Si Thammarat. 4.between Amphoe Thung Song in Nakhon Si Thammarat and Amphoe Huai Yot in Trang. 5.between Amphoe Sikao in Trang and Amphoe khlong Tom in Krabi. Eighty nine study locations were selected systematically in this 5 areas. The data used in this study were collected from 5 informants at each location who were chosen according to a set of oriteria. It was found that the dialect boundary between eastern southern Thai and western southern Thai on the basis of variation between /k/ and /?/ in the final position of long syllables is located in the five areas as stated in the hypothesis, the details are as follows. 1.The administrative boundary between Amphoe Muang and Amphoe Kanchanadit in Surat Thani. 2.The administrative boundary between Amphoe Nabon and Amphoe Lan Saka in Nakhon Si Thmmarat. 3.Ban Nong Wa in Amphoe Thung Song is the boundary location between Amphoe Thung Song and Amphoe Ron Phibun in Nakhon Si Thammarat. 4.Ban Wang Tao in the south of Amphoe Thung Song is the boundary location between Amphoe Thung Song in Nakhon Si Thammarat and King Amphoe Ratsada (formerly a part of Amphoe Huai Yot) in Trang. 5.The area between Ban Khlong Tom Tai and Ban Huai Nam Khao, Amphoe Khlong Tom in Krabi. When the boundary lines drawn in the five areas are considered together with the location of the mountain ranges, a complete picture of the dialect boundary between eastern southern Thai and western southern Thai may be seen beginning at the Gulf of Thailand in Surat Thani, moving south along the Nakhon Si Thammarat mountain ranges, turning west past the Na Daeng mountain ranges, and ending at the Andaman Sea.