Bengali (Bangla), part of the Indo-European language family, is the official language of Bangladesh and is spoken by about 98% of the population. The successful move to make Bengali coequal with Urdu as an official language was a hallmark of Bengali nationalism in the early 1950s. Non-Bengali migrants from India still speak Urdu (and Hindi) today, and this language is widely understood in urban areas. A few tribal groups, notably the tribal peoples of the Chittagong Hill Tracts, also speak distinct Tibeto-Burmese languages, akin to Burmese and Assamese. Among those speaking Bangla there are differences of dialect according to region. The people of Chittagong, Noakhali, and Sylhet are known for their distinctive dialects. Although today Bangla is the official language, English is also used for official and legal purposes and widely used in business.