"The British Isles were among the geographical areas affected by the Viking expansion from the 8th century onwards. North and west of the Danish Danelaw, Norwegian settlements were established on Shetland and Orkney, in Northern Scotland, on the Hebrides, along the west coast of Scotland and Northern England, around the Irish Sea and even further south. Raiders and conquerors at the outset, the Norsemen soon became traders and founded towns and states. The resulting language contact between Celtic and Old West Norse lasted half a millennium and left its mark on Norn, an early modern Nordic language spoken on Shetland, Orkney and in Caithness until the 18th century. Thus, Celticisms can be found both in the few written records of Norn and in the Nordic substratum of those varieties of Modern Scots that came to supplant Norn" --