In the 1981 Definitions, there is a very small piece of text that might almost be missed, which speaks volumes about a world that was perhaps coming to an end:
Text of explanation of Scottish gaelic question
Figure : Information on the definition of Scottish america rcs data Gaelic in the 1981 Census.
In 1981, the question on whether people could speak Gaelic was still asked in Scotland, but individuals were no longer asked if they could also speak English.
This was because the numbers returned in the 1971 Census were so low for Gaelic-only speakers that they would have been disclosive, meaning that there was a risk of individuals being identified from their responses.
What we can see here is, not a death of the Gaelic language itself, but an end to those communities who only ever spoke Gaelic and who never wanted or needed to learn English.
With the recent resurgence in use of the Gaelic language perhaps in the future we will see the questions asked once more.