trade; and the Malay language was formerly considered to be a lingua franca of the southern part of the Malay peninsula. Southern Thai is mainly a spoken language, although the Thai alphabet is often used in the informal situations when it is written. The words used that are etymologically Thai are often spoken in a reduced and rapid manner, making comprehension by speakers of other varieties difficult. Also, as Southern Thai uses up to seven tones in certain provinces, the tonal distribution is different from other regional varieties of Thai. Additionally, Southern Thai speakers almost always preserve ร as /r/ in contrast to Northern Thai, the Lao-based Isan language, and informal registers of Central Thai where it is generally realized as /l/. References Sources Bradley, David. (1992). "Southwestern Dai as a lingua franca." Atlas of Languages of Intercultural Communication in the Pacific, Asia, and the Americas. Vol. II.I:13, pp. 780–781. Levinson, David. Ethnic Groups Worldwide: A Ready Reference Handbook. Greenwood Publishing Group. ISPN: 1573560197. Miyaoka, Osahito. (2007). The Vanishing Languages of the Pacific Rim. Oxford University Press. . Taher, Mohamed. (1998). Encyclopaedic Survey of Islamic Culture. Anmol Publications Pvt. Ltd. . Yegar, Moshe. Between Integration and Secession: The Muslim Communities of the Southern Philippines, Southern Thailand, and Western Burma/Myanmar. Lexington Books. . Diller, A. Van Nostrand. (1976). Toward a Model of Southern Thai Diglossic Speech Variation. Cornell University Publishers. Li, Fang Kuei. (1977). A Handbook of Comparative Tai. University of Hawaii Press. . External links Southwestern Tai languages Languages of Thailand Languages of Malaysia Languages of Myanmar Malay Peninsula Peninsular Malaysia Southern Thailand