Robert McColl Millar 
Sociolinguistic History of Scotland [PDF ebook] 

Robert Mc Coll Millar examines how language has been used in Scotland since the earliest times. While primarily focusing on the histories of the speakers of Scots and Gaelic, and their competition with the encroaching use of (Scottish) Standard English, he also traces the decline and eventual 'death’ of Pictish, British and Norn. Four case studies illustrate the historical development of North East Scots, Scottish Standard English, Shetland Scots and Glasgow Scots. Immigrant languages are also discussed throughout the book.