This study investigates the significance of filled and unfilled pause phenomena as a universal strategy in language acquisition to achieve potential in communication across languages. Thai, the language of Thailand is used as a second language by speakers of different first languages as well as a first language in a natural setting, in Thai environment. The study, by way of contrastive analysis between speech samples of native and non-native speakers, provides statistical results on the distribution of pauses, with discussion of significant features which affect pauses and significance of pauses in conversations in Thai. As a result of the empirical testing of Thai spontaneous speech data, more information on Thai phonology has been revealed. Two corresponding types of pauses, filled pauses/pause fillers and unfilled/silent pauses are found in conversational Thai spontaneous speech. Filled pauses are categorized into two kinds,