The Ok languages are clearly related.
Alan Healey identified them as a family in 1962. He later noted connections with the
Asmat languages and
Awyu–Dumut families (Healey 1970). Voorhoeve developed this into a
Central and South New Guinea (CSNG) proposal. 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) claim to have demonstrated that the erstwhile TNG isolate
Oksapmin is related to the Ok family. However, this has not been generally accepted because loans from Mountain Ok have not been accounted for. Van den Heuvel & Fedden (2014) argue that Greater Awyu and Greater Ok are not genetically related, but that their similarities are due to intensive contact. ==Languages==