The Thai language, with northern, eastern, central (Bangkok or official Thai), and southern dialects, all distantly related to Chinese, prevails throughout the country. Thai, written in a distinctive alphabet, is thought to be part of the Sino-Tibetan language family, although links to Indian languages are also evident. The Thai dialects for the most part are mutually intelligible only with difficulty. Although the ethnic minorities (including the Malays) generally speak their own languages, Thai is widely understood. The Chinese population is largely bilingual. All official documents are in the central Thai language and script, although English, taught in many secondary schools and colleges, is also used in official and commercial circles.