The morphology of -ly and the categorial status of ‘adverbs’ in English

I argue in this article that adverb-forming -ly, unlike its adjective-forming counterpart, is an inflectional suffix, that therefore adverbs containing -ly are inflected adjectives and that, consequently, adverbs not containing -ly are uninflected adjectives. I demonstrate that in English, the traditional category Adverb is morphologically non-distinct from the category Adjective in that it has no morphology of its own but instead shares all relevant aspects of the morphology of adjectives. I demonstrate moreover that such an analysis explains various aspects of morphological and phonological behaviour on the part of adverbial -ly which differ from the behaviour of adjectival -ly and/or from the behaviour of derivational suffixes. And I argue that contrary to a recent claim, the syntactic behaviour of adverbs presents no obstacle to the single-category analysis of adjectives and adverbs warranted by the morphology.