At the People’s Gathering, in passing, someone said that all official documents in Scotland should be in “all three languages” – English, Scots, and Gaelic.
A sprakh is a dialekt mit en army un flot. – Max Weinreich
These days, it might be said that a language is a dialect with TV programmes and schools. I don’t know how you’d say that in Yiddish. Back when Scotland had an army and a navy, the language spoken through most of Scotland was referred to by its speakers as Inglis – it acquired the name of Scots only when Scotland had ceased to have either. (R.L.G. discusses the Scandinavian languages, which are similiar-but-politically-distinct.)
Lallans exists as a written language: spoken Scots has four main geographic “families”: Insular Scots of Orkney and Shetland; Northern Scots of Caithness, Easter Ross, Moray, Aberdeenshire and Angus; Central Scots of Central Lowlands and South west Scotland; and Southern Scots of the Scottish Borders and Dumfriesshire. (Plus, Scots-Yiddish and Scottish BSL.)