Norn was a language left behind by Viking settlers from the eighth century. Norn was spoken in the archipelagos of Orkney and Shetland in NW UK. Surprisingly, the language didn’t die quickly, it persisted for a few centuries after Norway handed over the two archipelagos to Scotland in 1468. It died with the last speaker, Walter Sutherland in 1850, however, the language was easily still well-intertwined with the local dialect of Scots until 1900. Even today, remnants of Norn remain in Orkney and Shetland Scot’s vocabularies in a few areas.
Based upon the etymological dictionary written by Jakob Jakobsen in 1896, Norn contains much of the same grammatical features that its sister languages share, such as having three genders (masculine, feminine and neuter), and four grammatical cases (nominative, accusative, genitive, and dative). A new language called Nynorn takes from this dictionary and Norse linguistics to reconstruct a language for daily use. Progress on this project will be interesting to see develop over the next few years.
The language appeared to be closest to Faroese, sharing some features with Icelandic and its verb conjugation structure must have borrowed from Norwegian, given family ties may have stretched there as late as the 18th century.
Check out this video on Norn that I made, it is longer than usual since a background about the language needed to be given for context.
Check out this website on Nynorn. It also has information on the Norn spoken on mainland Scotland, and both archipelagos. It has a wealth of information on the history of the language as well. http://nornlanguage.x10.mx/
Check out these other fantastic resources on Norn: the second resource is especially informational.
Trudgill, Peter (1984). Language in the British Isles. Cambridge University Press. p. 361. ISBN 978-0-521-28409-7
Barnes, Michael P. The study of Norn Northern Lights, Northern Words. Selected Papers from the FRLSU Conference, Kirkwall 2009.