This article aims to show how to understand a language phenomenon through the language play of the Thai. The data is based on Tamjai (2003): Mechanisms and Patterns of Reversed Speech in Bangkok Thai, Northern Thai, Northeastern Thai, and Southern Thai, and Southern Thai Dialects. There are 334 utterances used to analyze the status of /-w-/. The Thai speakers of three dialects, Bangkok Thai, Northern Thai, and Southern Thai dialect speakers, interpreted the status of /-w-/ in five different types when reversed the utterances. Firstly, the second phoneme of an initial cluster: /-w-/. Secondly, the single phoneme of an initial consonant: /-w-/. Thirdly, the property of vowel: /ṷ/. Fourthly, the vowel: /u/. Finally, the zero: /ø/. The results according to McMahon (1994) about the stages of sound change. Moreover, the status of /-w-/ form reversing the utterances show how the sound changed from Proto South Western Tai to Modern Tai; Yuan, Lao, and Siamese.