Abstract:
The main purpose of this study is to investigate the tone system of Central Thai spoken in every Amphoe of Ang Thong and Phra Nakhorn - Si Ayutthaya in order to identify the sub-dialects in the area. Monosyllabic and polysyllabic words spoken in isolation were elicited from 23 informants who represent local speakers of Central Thai in the 23 Amphoes of the two provinces. They were chosen according to a set of criteria. The study shows that the dialect spoken in the area of study can be devided into sub-dialects. The .subdivision on the basis of the phonetic characteristics of each tone differs from that on the basis of the whole tone system. The phonetic characteristics of tone 1, tone 2, tone 4 and tone 5 divide the dialect into three sub-dialects whereas those of tone 3 divide the dialect into two sub-dialects. The area where each sub-dialect is spoken varies from tone to tone. The tone system as a whole divide the dialect into four sub-dialects : the Ang Thong sub-dialect, the Western Ayutthaya sub-dialect, the Central Ayutthaya sub-dialect and the Eastern Ayutthaya sub-dialect. A new method for studying tonal variation is suggested in this study. It uses a set of distinctive characteristics which differentiate the sub-dialects. These characteristics are of two kinds : those pertaining to the rate of the occurence of each pitch pattern and those pertaining to the existence or non-existence of a pitch pattern.