You know what I’ve been seeing a lot of recently? Hyphenated compounds with -ly adverbs. (Yeah, I know, probably not your first guess.) As in, “a fully-developed plan” or “their formerly-intractable armies.” I’m right in thinking this is wrong…um, right? I don’t have a lot of grammatical pet peeves — spelling “ridiculous” with an -e is usually one of them; so is that old Harry Potter staple “He said darkly” — but this has actually been bugging me lately.
I think it’s more because it’s briefly cast doubt on what I thought I knew about grammar, and less because it’s a particularly important or vital rule. I am, in fact, having a tough time — and so would welcome any examples you might have in the comments below — of specific cases where the meaning of a phrase would be different (and thereby rendered confusing) with the hypen than without. I mean, that’s ultimately the purpose of grammar: not to force us all to speak and write the same way, but to alleviate the confusion that often arises when we don’t.
One can never be certain (given the extent to which English changes every day), but I always nixed the hyphen in cases of adverb-adjective-noun constructions. So not just “fully developed plan” but also “well developed plan.”
But, of course, “computer-developed plan,” because then you’re talking about the development, which used a computer, because the plan didn’t.
I think, anyway.
If I’m remembering correctly, back in the mists of time, I was taught in elementary school that “ly” signifies an adverb, which may modify a verb or an adjective. Thus, much as an adjective modifies a noun, there is no need to add a hyphen.