The South Halmahera–West New Guinea (SHWNG) languages are a branch of the Malayo-Polynesian languages, found in the islands and along the shores of the Halmahera Sea in the Indonesian province of North Maluku and of Cenderawasih Bay in the provinces of Papua and West Papua.

Blust (1978) has proposed that they are most closely related to the Oceanic languages, but this classification is not universally accepted.

[2] Most of the languages are only known from short word lists, but Buli on Halmahera, and Biak and Waropen in Cenderawasih Bay, are fairly well attested.

There are few lexical similarities with present-day Papuan languages, except for a few words such as 'sago' that are shared with the two tonal Papuan isolates Abun and Mpur (both spoken on the north coast of the Bird's Head Peninsula):[6]: 134–135 However, Arnold (2018) traces this etymology to proto-Malayo-Polynesian *Rambia 'sago palm'.

[8] The mutation is found in the Ambai, Ansus, Biak, Busami, Dusner, Kurudu, Marau, Meoswar, Moor, Munggui, Papuma, Pom, Roon, Roswar (possibly equivalent to Meoswar), Serewen (possibly a dialect of Pom), Serui-Laut, Umar, Wamesa, Warembori, Waropen, Wooi, Yaur, Yerisiam, and Yoke languages.