The Tasmanian languages/dialects records are sparse. Crowley and Dixon say North Midlands (T4) is probably a distinct language; the language data coincide with Cape Portland (54%) but not with Port Sorrell (19%), making a language group between them and the Ben Lomond T7 data unlikely (1981:402). Crowley (1993:54) concludes from examination of vocabulary lists and comments from colonial observations about who could and who could not understand each other, that at least eight separate languages and possibly as many as twelve belong to Tasmania. Crowley and Dixon (1981:404) conclude there is no evidence to indicate a single Tasmanian language family, available evidence indicates two, four or even eight distinct families.

Bowern (2012) groups twelve languages into four language macro-families (northeastern, Oyster Bay, southeastern (Bruny) and western) using methods from evolutionary biology to systematically investigate vocabularies, from thirty five language lists.

Crowley and Dixon (1981:402-403) compare collected vocabularies from fifteen regions. This database assigns reference names for Tasmania based on this regional list. See also Northern T1; Oyster Bay T2; North-western T3; South-eastern T5; Macquarie Harbour T6; Ben Lomond T7; Big River T8; Cape Portland T9; South-western T10; Robbin Island T11; Circular Head T12; Port Sorrell T13; Piper River T14 and Little Swanport T15. The area defined as North Midlands in Crowley and Dixon's map (1981:394) roughly coincides with the area defined as Tyerrernotepanner by Horton in the AIATSIS map of Aboriginal Australia. Northern Midlands Tasmanian language data, along with historical sources from all Tasmanian language varieties form the basis of palawa kani language T16.