The original language of Brussels was a form of Flemish (Vlaams), itself a dialect of Dutch (Nederlands), known as Brabants, which evolved following the arrival of the Franks in the region in the fifth century. Brussels Dutch, usually referred to by residents as Brussels, is one among a number of dialects of Brabants spoken in Brabant that are generally identified by local inhabitants as Ander-lechts, Molenbeeks, and so forth. In addition, Dutch dialects from elsewhere in Belgium are spoken by immigrants from Flanders. Belgian Dutch (Flemish) is a regionwide variant encompassing all of Flanders that makes use of many distinctive idioms and dialecti-cisms. Standard Dutch is an official language of Belgium and the language of public instruction, commerce, and communications.
Dutch was widely spoken in Brussels until the beginning of the 19th century, when French began making substantial inroads. Following the rise to predominance of the latter, Dutch-language activities focused, at first, on cultural matters followed by growing demands for parity for the language in administrative, judicial, and political affairs, a process that culminated in creation of the bilingual Brussels Capital Region (BCR) in 1989.
Brussels Dutch is dying out—it is spoken today largely by very elderly residents — despite efforts to preserve the dialect exemplified by establishment of an Academic van het Brussels Dialect. Dutch speakers who move to Brussels from elsewhere generally speak standard Dutch.
The language is spoken today by approximately 15 percent of native-born metropolitan residents. Dutch speakers are concentrated in northwestern areas of the BCR. There has been a growth in use of Dutch in recent years, including in sections of the central city such as the Saint-Géry area.
Historical Dictionary of Brussels. Paul F. State.