Skou languages
The Sko or Skou languages are a small language family spoken by about 7000 people, mainly along the coast of Sandaun Province in Papua New Guinea, with a few being inland from this area and at least one just across the border in the Indonesian province of Papua (formerly known as Irian Jaya). Skou languages are unusual in New Guinea for being tonal. Vanimo, for example, has three tones, high, mid, low.
Currently there are linguists working on most of these languages, writing grammars, compiling dictionaries, and assisting the speakers to develop vernacular materials for use in schools.
Classification
Skou languages were first linked by G. Frederici in 1912. In 1941, K.H. Thomas expanded the family to its current extent.
Sko (Laycock 1975)
Laycock posited two branches, Vanimo and Krisa:
Vanimo branch – Skou, Sangke (Nyao), Wutung, Vanimo (Dumo)
Krisa branch – I’saka (Krisa), Rawo, Puari, Barupu (Warapu)
Skou (Ross 2005)
However, Krisa is poorly supported and Malcolm Ross abandoned it,