WITH ONLY a few exceptions, such as then and why, English adverbs are categorized as content words that express referential meanings in both the physical and abstract worlds. Like nouns and verbs, they belong to the ‘open’ class of lexemes, in which new words can be created through processes that include compounding, derivation, and borrowing. From compounding come adverbs such as hopefully (formed from the noun hope and the adjective full, plus the suffix -ly), and upstage (from the preposition up and the noun stage). By derivation, adverbs are formed from adjectives by adding -ly (as in economical-ly, sufficient-ly, and final-ly). As for borrowing from other languages, we have for example taken a range of expressions from Latin and used them as adverbs (as with ipso facto, ad nauseam, and ad infinitum).