This study is an investigation of syntactic ambiguity in Thai . Based on approximately 80 pages of Thai texts from four registers, namely legal register, political register, media register, and academic register, the study aims to analyze syntactic patterns that induce ambiguity, and to find out which patterns create the most ambiguities and in which registers. Also, devices to avoid such ambiguities are proposed. 

The analysis reveals that there are four types of syntactic patterns involving ambiguities: (1) modification construction, (2) coordination construction, (3) modification+coordination construction, and (4) anaphora. The results of the quantitative analysis show that modification construction accounts for more than half of all ambiguities in the study, followed by the modification+coordination construction, coordination construction, and anaphora construction, respectively. Compared across registers, it is found that the media register carries the most ambiguities, followed by the legal register, political register, and academic register, respectively. 

To avoid ambiguity, revisions of text are proposed. Ambiguous attachment sites of modifiers can be prevented by constituent reordering and nominal clauses. For the coordination construction, the subject of each of the verbal conjoins should be overt , and coordinators should be consistent for a series of items. In some cases, selected disambiguating materials would also be useful. Either a conjoinswitching technique or the provision of modifiers to both or all conjoined heads would clarify ambiguous modification+coordination constructions. When anaphoric ambiguity is potential, preferred is the repeated use of a word or phrase.