According to the Ethnologue, Indonesian is modelled after Riau Malay, a form of Old Malay originally spoken in Northeast Sumatra.Indonesian slang language is mostly spoken in urban regions of the Indonesian archipelago.

While it would be unusual to communicate orally with people on a casual basis with very formal Indonesian, the use of proper or 'good and correct' Indonesian ("bahasa Indonesia yang baik dan benar") is abundant in the media, government bodies, schools, universities, workplaces, amongst some members of the Indonesian upper-class or nobility and also in many other more formal situations. This is, in part, due to its vocabulary that is often so different from that of standard Indonesian and Malaysian and also because so many new words (both original and foreign) are quite easily incorporated into its increasingly wide vocabulary list.

However, as with any language, the constant changing of the times means that some words become rarely used or are rendered obsolete as they are considered to be outdated or no longer follow modern day trends.

At present, there is no formal classification for Indonesian slang language as it is essentially a manipulated and popularized form of the Indonesian (the national language of Indonesia).

Indonesian is part of the Western Malayo-Polynesian subgroup of the Malayo-Polynesian branch of the Austronesian languages.

the language of the original inhabitants of Jakarta or Batavia as it was known during the Dutch colonial period).

For more information relating to the geographics of Indonesian slang and regional influences, please see "Region Specific Slang" below.Indonesian slang language is not an official language of Indonesia.Indonesian slang (bahasa gaul or bahasa prokem) is informal language in Indonesia.Despite its direct origins, Indonesian slang often differs quite significantly in both vocabulary and grammatical structure from the most standard form of Indonesia's national language.Its native name, bahasa gaul (the 'social language'), was a term coined in the late 1990s where bahasa means 'language' and gaul means 'social', 'cool' or 'trendy'.Similarly, the term bahasa prokém (a more out-dated name for Indonesian slang) created in the early 1980s means 'the language of gangsters'.