The national language of Brunei is Standard Malay (Bahasa Melayu). While many countries promote a national language, few have a road sign in the middle of the capital prominently encouraging its usage:

Why is there this effort to promote the use of Malay? While nearly everyone in Brunei speaks Malay, it is the local variety, known as Brunei Malay, that generally occurs, and Brunei Malay is completely different from Standard Malay. The government believes that it is important to promote the use of Standard Malay, to allow people to communicate with people in Malaysia, Indonesia, and Singapore, and to read books and newspapers and understand official broadcasts.
We can describe Standard Malay and Brunei Malay as two dialects of the same language existing in a diglossic relationship. Diglossia describes the situation where two language varieties have complementary roles:
- the H (= High) language, is used in official communications and in the classroom;
- the L (= Low) language, is used at home, among friends, and in most colloquial exchanges.