Speaking a language with any degree of fluency requires a knowledge of idioms, proverbs, slang, fixed expressions, and other speech formulas. A traditional view of idioms and related speech formulas sees these phrases as bits and pieces of fossilized language. Yet idiomatic/proverbial phrases like the above are not mere linguistic ornaments, intended to dress up a person's speech style, but are an integral part of the language that eases social interaction, enhances textual coherence, and, quite importantly, reflect fundamental patterns of human thought. Idioms and many formulaic expressions are not simple fixed or frozen phrases. In many cases, idioms are analyzable to varying degrees and linked to enduring metaphorical and metonymic conceptual structures. Over the past twenty-five years, cognitive linguistic research has played a significant role in advancing this new vision of idiomaticity. My aim in this chapter is to describe this revolution, of sorts, in the linguistic and psychological study of idioms and related speech formula. (Raymond Gibbs)