|Madang and Morobe Provinces, Papua New Guinea|
The family of Markham languages is a family of the Huon Gulf languages. It consists of a dozen languages spoken in the Ramu Valley, Markham Valley and associated valley systems in the lowlands of the Madang and Morobe Provinces of Papua New Guinea. Unlike almost other Western Oceanic languages of New Guinea, which are spoken exclusively in coastal areas, many Markham languages are spoken in the mountainous interior of Morobe Province, Papua New Guinea, where they are in heavy contact with Trans-New Guinea languages.
A phonological reconstruction of Proto-Markham is presented in Holzknecht (1989).
Labu (= Hapa)
The most comprehensive survey of the Markham languages is The Markham Languages of Papua New Guinea by Susanne Holzknecht, which established a common descent from Proto Huon Gulf. It did so on the basis of shared phonological, morphosyntactic and lexicosemantic innovations.