its pretty clear from these that INFORMAL language was the focus of at least this body of research, but actually this is most of theoretical linguistics here

usually our examples aren't so vulgar -- the Generative Semanticists were trying to bring some levity to an otherwise boring tradition of boring example sentences and so they intentionally constructed examples that were obnoxious and funny and gross and whatnot because science should be fun -- but nevertheless, most theoreticians work in casual speech, not formal speech