Restrictive and Nonrestrictive Clauses

This is dumb but I got an email that started "Today we are marking International Day Against Homophobia, Transphobia and Biphobia" and my sleepy brain's first thought was, OK more marking.

Anyway. In the midst of marking I had a flashback to Standard Four with Mr Cooper and "that" and "which" and restrictive and nonrestrictive clauses, and me not really believing it. And I still don't really believe it.

Microsoft Word Grammar Checker I'm looking at you.

Consider this should-be-straightforward example of a nonrestrictive clause:

Jo Walton, who wrote Among Others, is a brilliant writer.

... taking this inkling any further would involve exploring how "narrowing down a set" is maybe a clunky and misleading model for both the phenomenology and the metaphysics of reference. I'd probably have to remind myself what intensionality is again. Thank God for marking.

Somebody write this

Speculative fiction writers. In this culture, whenever anybody speaks more than a very brief phrase -- more than three words, let's say -- they end their statement with an extra word. This word stands outside the ordinary grammar of the statement. Whoever answers is bound by deep cultural logic to weave this extra word into their answer. If they were to omit the word, then to the ears of this people, they wouldn't even have made speech, just babble.