Biak (wós Vyak or 'Biak language'; wós kovedi or 'our language'; Indonesian: bahasa Biak), also known as Biak-Numfor, Noefoor, Mafoor, Mefoor, Nufoor, Mafoorsch, Myfoorsch and Noefoorsch, is an Austronesian language of the South Halmahera-West New Guinea subgroup of the Eastern Malayo-Polynesian languages.

According to Ethnologue, it is spoken by about 70,000 people in Biak and Numfor and numerous small islands in the Schouten Islands, located in Papua province of Western New Guinea, northeastern Indonesia.

The name Biak or Vyak refers to the island of the same name. It probably comes from an earlier form *Bat, which is argued to have meant "the ground under one's feet, land" in Proto-Austronesian via the regular change of *t to k. This is supported by the Ambel cognate Báyt.

There are a number of different dialects of Biak spoken on various different islands, the most well-known being Biak-Numfoor, spoken on the island of Numfoor. These dialect differences are minor and mostly limited to slight regular sound changes. The vast majority of Biak speakers are also fluent in the local variety of Malay, but not all of them are proficient in standard Indonesian.

Geographical distributions of Biak dialects within Raja Ampat Regency (Ronsumbre 2020):

Despite the comparatively high number of speakers compared to some other Austronesian languages, Biak is still in danger of extinction. Within the main towns, the generation of speakers aged between 20 and 50 have only passive knowledge of the language and rarely use the language actively, instead preferring to use Malay. Younger generations do not even generally have passive knowledge of the language. Biak is only actively used as a spoken language by members of the community over 50 years of age or so and even they regularly code switch into Malay. However, within the villages further from town there are still children who are fluent in Biak. Songs in Biak are also very popular throughout the islands.

There is a strong initiative to promote the use of the Biak language, with translations of various books and teaching manuals as well as a radio station and a number of church services throughout the year being conducted solely in Biak. Since 2002, there has also been an initiative to introduce Biak being taught formerly in schools on the islands.

Biak has a phoneme inventory consisting of 13 consonants and 5 vowels, in which vowel length is phonemic. In the orthography long vowels are written with an acute accent. The phoneme /t/ is very infrequent in its use and some older speakers still realise it as [s] in loanwords.