Urdu was chosen as an official language of Pakistan in 1947 as it was already the "lingua franca" for Muslims in north and northwest British India, although Urdu had been used as a literary medium for colonial Indian writers from the Bombay Presidency, Bengal, Orissa Province, and Tamil Nadu as well. In 1973, Urdu was recognised as the sole national language of Pakistan – although English and regional languages were also granted official recognition. Following the 1979 Soviet Invasion of Afghanistan and subsequent arrival of millions of Afghan refugees who have lived in Pakistan for many decades, many Afghans, including those who moved back to Afghanistan, have also become fluent in Hindi-Urdu, an occurrence aided by exposure to the Indian media, chiefly Hindi-Urdu Bollywood films and songs.