It may be appropriate to distinguish between compound modifiers whose adverb has the suffix "", such as "quickly" and "badly", and those whose adverb does not, such as "well". The "-ly" suffix on an adverb allows readers to understand its lexical category (if not in the technical sense, then at least in the sense of the intended meaning), showing that it is intended to modify the adjective that it precedes and so not requiring hyphenation. "Quickly" and "badly" are unambiguously adverbs.