[1][2] If valid, it would be the largest demonstrated family of Malayo-Polynesian outside Oceanic.

The Malayo-Sumbawan subgroup is however not universally accepted, and is rejected e.g. by Blust (2010) and Smith (2017), who supported the Greater North Borneo and Western Indonesian hypotheses.

[3][4] In a 2019 paper published in Oceanic Linguistics, Adelaar accepted both of these groupings, in addition to Smith's (2018) redefinition of Barito languages as forming a linkage.

[5][6] According to Adelaar (2005), the composition of the family is as follows:[1] Unlike in earlier classifications of the languages of the Greater Sunda islands (e.g. Isidore Dyen's "Sundic" subgroup in his 1965 lexicostatistical classification of the Austronesian languages,[7] which included all languages later included in Adaelaar's proposal plus the Southwest Barito languages, Javanese, Gayo and Lampung), Javanese is specifically excluded; the connections between Javanese and Bali–Sasak are mainly restricted to the 'high' register, and disappear when the 'low' register is taken as representative of the languages.

This is similar to the case of English, where more 'refined' vocabulary suggests a connection with French, but basic language demonstrates its closer relationship to Germanic languages such as German and Dutch.