With the advancement of the Internet technology, customers can easily share opinions about services and products in forms of reviews. There can be large amount of reviews for popular products. Manually summarizing those reviews for important issues is a daunting task. Automatic opinion summarization is a solution to the problem. The task is more complicated for reviews written in Thai. Thai words are written continuously without space, and there is no symbol to identify the end of a sentence. Many reviews are written informally, thus accurate ...