Greenlandic Norse is an extinct North Germanic dialect that was spoken in the Norse settlements of Greenland until their demise in the late 15th century. The language is attested through some 80 runic inscriptions, many of which are difficult to date and not all of which were necessarily carved by people born in Greenland.
It is difficult to identify specifically Greenlandic linguistic features in the limited runic material. Nevertheless, there are inscriptions showing the use of t for historical þ in words such as torir rather than þorir and tana rather than þana. This linguistic innovation has parallels in West Norwegian in the late medieval period. On the other hand Greenlandic appears to have retained some features which changed in other types of Scandinavian. This includes initial hl and hr, otherwise only preserved in Icelandic, and the long vowel œ, which merged with æ in Icelandic but was preserved in Norwegian.
Greenlandic Norse is believed to have been in language contact with the Kalaallisut language, the language of the Kalaallit, the then local Inuit people, and to have left loanwords in that language. In particular, the Kalaallisut word Kalaaleq (older Kakkalaaq), originally meaning quite the strong/courageous/gutsy one, is believed to be derived from the Norse term for the people they befriended upon encountering in the south, south-west coasts of Greenland. It is also known that the word kona, meaning wife, is of Norse origin as it is also the Icelandic translation of the word, and the word "kvinna" meaning "woman".
The available evidence does not establish the presence of language attrition, the language most likely disappeared with the ethnic group that spoke it.