The southwestern part of the island is occupied by the unrelated South Halmahera languages, which are a subgroup of Austronesian.

[4] Others exhibit deep external influence, having shifted to a more Austronesian-type grammar as a consequence of prolonged contact.

[11]: 364  However, Ger Reesink notes that the evidence for genetic relatedness between the different "West Papuan" groupings is too skimpy to form a firm conclusion,[1] suggesting that they be considered an areal network of unrelated linguistic families.

[12] The ethnic groups of the north Halmahera area share civilizational links with the Islamic world and the populations of western Indonesia, betraying a mismatch between cultural and linguistic affiliation.

Cowan (1957–1965), linking NH with the Bird's Head languages, among others (based on lexical and morphemic evidence).

[3][14] In addition, Ternate, Tidore, West Makian, and Sahu have adopted many elements of Austronesian grammar;[2][3] however, other languages of the family are rather conservative, having preserved the SOV word order, the use of postpositions, as well as the use of object and subject prefixes.

While different authors tend to disagree on the number of distinct languages identified,[15] there is general accord regarding the internal subgrouping of the family.

They are probably best considered separate languages, as mutual intelligibility testing appears to be skewed by the cultural practice of multilingualism.

[20] The words cited constitute translation equivalents, whether they are cognate (e.g. utu, hutu for “hair”) or not (e.g. dofolo, apota for “head”).