This article aims to depict the patterns of language use of Muslims who are ethnic Malay and
use Pattani Malay as their mother-tongue in the southernmost provinces of Thailand (Pattani, Yala,
Narathiwat, Satun and some parts of Songkhla).The data used for this article is based on the
examination of documents and interviews of teachers and people in the region including the writer’s
personal observation as a person who has been living in the Muslim community in Songkhla province
for more than thirty years. It is found that the patterns of language use among these people shows a
consistent diglossic practice. Standard Malay and Arabic are used in Islamic education. Standard Thai is
used widely in government, education and in formal situations with strangers. Pattani Malay and
Southern Thai are informal languages used with in-group and out-group in informal situations.For the
education policy in the southernmost provinces, the article recommends that instead forcing Muslim
students to study only Thai in government schools, it is better to promote bilingualism in both
government schools and Islam private schools.