As part of CSNG, the Ok languages form part of the original proposal for Trans–New Guinea, a position tentatively maintained by Malcolm Ross, though reduced nearly to Healey's original conception.

Ross states that he cannot tell if the similarities in CSNG are shared innovations or retentions from proto-TNG.

Voorhoeve argues specifically for an Awyu–Ok relationship, and Foley believes that these two families may be closest to Asmat among the TNG languages.

Loughnane and Fedden (2011)[3] claim to have demonstrated that the erstwhile TNG isolate Oksapmin is related to the Ok family.

[4] The languages are: The following are consonants of Proto-Ok:[5] Vowels may be /*iː *ʉ *uː *e *a *o/, but this reconstruction may be biased toward Telefol.