The history of the Scots language refers to how Anglic varieties spoken in parts of Scotland developed into modern Scots.
Speakers of Northumbrian Old English settled in south eastern Scotland in the 7th century, at which time Celtic Brythonic was spoken in the south of Scotland to a little way north of the Firth of Forth and the Firth of Clyde, and Pictish was spoken further north: almost nothing is known today about the Pictish language. At the same time Gaelic speakers began to spread from the Western Coast of Scotland north of the Clyde into the east. Over the next five hundred years with the founding of Scotland and spread of Christianity across the north of Britain by the Columban Church the Gaelic language slowly moved eastwards and southwards across the lowlands. When Northumbrian lands were incorporated into Scotland in the 11th century Gaelic became the prestige language there and had some influence, but the south east remained largely English speaking. In the far north, Viking incursions brought Old Norse speakers into Caithness, Orkney and Shetland.
Scholars of the language generally use the following chronology:
The nature of early forms of the language are obscure due to Viking plundering and destruction, Edward I of England's removal of the national records and their subsequent loss, the destruction of the monasteries in border warfare, and vandalism during the Reformation. It is difficult to assess whether Scots descends largely from the Old English of Lothian or the Anglo-Danish of Yorkshire introduced some four hundred years later, which would explain the Norse elements in Early Scots which are lacking in Northumbrian Old English. Current insights into pre-literary Scots stem largely from place-names, archaeology and a few words in Latin documents.