This is an indirect way of implying that Scots is not a language, nor is it even the equal of an English dialect. Metropolitan English does have a strong suppressing effect, on dialects within itself and on other, neighbouring languages.
Scots, however, has had a robust written canon since about 1300, when it was used, with Latin, for charters, and later for lawmaking, allowing the statutes to be "cried frae the Cross", that is, publicly announced, in the language of the burghs, Scots.
These early Scots records predate Chaucer by 50 years. He was instrumental in removing English from the hegemony of Norman French, under which it had languished since 1066.
This reinforces Dr David Purves' point that language status is related to political power (Letters, 24 December). In a similar fashion Scots is overshadowed by English, but certainly not to the degree adumbrated by Mr Oliver.
IAIN WD FORDE