Ordnance Survey Memoirs, Donaghadee, 1837

Here's another quote demonstrating the scale of 'Scotch' speech in east Ulster in the 1800s – this is from the Ordnance Survey Memoirs from 1837. When you gather all of the contemporary references up, Belfast was entirely encircled by Ulster-Scots vernacular speech – and it was of course evident within the growing city too when those people moved in for the industrial 'boom'. The children of farmers became world-class engineers, and the old individual wooden hand-loom cottage weavers became mechanised maestros, running factories and leading battalions of labourers who had learned to master vast steel-and-iron behemoths that produced acres of fine linen fabric which rivalled silk. 

When Scotsman Rev Dr James McCosh LLD was at Queen's College in Belfast from 1850–1868. His autobiography says that "The plain people … were earnest in their devotion to the cause of liberty, and so also were their friends and relatives among the Ulster farmers. The classes of Queen's College had many members from among these enterprising, industrious, serious people, and Professor McCosh became deeply interested in them". (online here)

His fellow Scot and Queen's College colleague Professor George Lillie Craik spoke at the Burns Centenary events in Belfast in 1859, and said "we have come over and set up another Scotland here - an Irish or Little Scotland, as it may be called. We have made this Province of Ulster - this Black North - half Scotch, or more than half Scotch, in almost everything – in blood, in language, in religion, even in mind and character ...".

This all sets a far more plausible demographic context for the Census of Ireland in 1911, in which the population was given two options of 'Irish' and 'English' to describe their language, and vast numbers in Antrim and Down opted for 'Irish'. It's extraordinarily unlikely that they meant Gaeilge.

Here is Barry Griffin's excellent map again, showing the familiar and well-attested Gaeltachts of the west – but which also reveals another vast 'non-English' linguistic tradition and community in the east.