The Bosavi or Papuan Plateau languages belong to the Trans-New Guinea language family according to the classifications made by Malcolm Ross and Timothy Usher. This language family derives its name from Mount Bosavi and the Papuan Plateau.

Geographically, the Bosavi languages are situated to the east and south of the East Strickland group. They can be found around Mount Bosavi, located east of the Strickland River and southwest of the western edge of the central highlands of Papua New Guinea. Although no extensive subgrouping analysis has been conducted, Shaw's lexicostatistical study in 1986 provides some insights.

Based on this study, it is indicated that Kaluli and Sonia exhibit a significant lexical similarity of 70%, which is higher than any other languages compared. Therefore, it is likely that these two languages form a subgroup. Similarly, Etoro and Bedamini share a subgroup with a lexical similarity of 67%. The languages Aimele, Kasua, Onobasulu, and Kaluli-Sunia exhibit more shared isoglosses among themselves than with the Etoro-Bedamini group. Some of these shared isoglosses are likely to be innovations.^[1]

The languages, which are closely related are:^[1]

• Mount Bosavi: Kaluli–Sonia, Aimele (Kware), Kasua
• Onobasulu
• Mount Sisa: Edolo–Beami
• Dibiyaso (Bainapi)

Its worth noting these languages share at best 70% lexical (vocabulary) similarity, as in the case of Kaluli-Sonia, and Edolo-Beami.^[1] The rest of related languages likely shares around 10-15% lexical similarities.

The unity of the Bosavi languages was quantitatively^{[clarification needed]} demonstrated by Evans and Greenhill (2017).^[2]

Palmer et al. (2018) consider Dibiyaso to be a language isolate.^[3]

Pronouns are:

The following basic vocabulary words are from the Trans-New Guinea database:^[4]