most indonesian, aside from speaking the national language, are often fluent in another regional language examples include chiness language which are commonly used at home and with in the local community. most formal education, as well as nearly all national media and other forms of communication, are conducted in indonesian. in east timor, which was an indonesian province from 1975 to 1999, indonesian is recognized by the constitution as one of the two working language ( the other is english, alongside the official language of tetum and portuguese.