When the Dutch conquered Indonesia in the 1600s, the islanders spoke hundreds of different languages. In 1928, the leaders of the independence movement rather arbitrarily chose one, which they dubbed Bahasa Indonesia, to become the national tongue, and after independence required that it be taught in all schools. But many Indonesians, especially the poor, continued to speak their native languages (Javanese, etc.) and some of the elite continued to speak Dutch. Now much of the Indonesian elite prefers to send their children to private schools where they are educated in English, and there has also been a resurgence of some of the local languages. Bahasa Indonesia is squeezed in between, and some people worry that it is threatened. Before you fret about the spread of imperial English and the loss of local culture, remember that Bahasa Indonesia is not the native language of most Indonesians, but something they have to learn in school. Many of them are deciding that if they have to learn a second language it might as well be one that will help them get ahead in the world. There is also a political angle, because the Suharto dictatorship tried to force the use of Bahasa Indonesia and ban the local languages from public use, so some people see using their native tongues as an assertion of freedom.
I wonder if Bahasa Indonesia will fade away over the next few decades and Indonesia will become like India, where English is the common tongue for people who speak many different languages at home.