Final particles are very interesting to study because they make sentences sound more natural and their meanings clearer. Through the usage of final particles ,emotions ,feelings, politeness ,status ,and speaker’s attitudes towards the listeners are expressed. Failure to use final particles or abusing the use of final particles can create misunderstanding between the speakers and the listeners. This research analyzes final particles in conversational Lao Isan Language used in the Isan region of Thailand . The data were collected from TV dramas, and conversations among native speakers. The syllable structure, the use of final particles, as well as their free variations are discussed. Sociolinguistic concepts, the social factors that influence the selection of usage of these final particles, were also included in the analysis. The study finds that social factors involved in the selection of the usage of final particles are genders of the speakers, the status of the speakers and listeners, the intimacy between the speakers and listeners. Degree of politeness expressed though the usage of final particles is also considered. Other factors that are found to influence the selection of final particles are situations, objectives of verbal communication, feeling, and most of all sentence modes, which include statements ,questions, commands as well as warnings, and requests as well as persuasions. There are free variations in some tones, some initial consonants, and some vowels of final particles.