A considerable proportion of our everyday language is 'formulaic'. It is predictable in form, idiomatic, and seems to be stored in fixed, or semi-fixed, chunks. This book explores the nature and purposes of formulaic language, and looks for patterns across the research findings from the fields of discourse analysis, first language acquisition, language pathology and applied linguistics. It gradually builds up a unified description and explanation of formulaic language as a linguistic solution to a larger, non-linguistic, problem, the promotion of self. The book culminates in a new model of lexical storage, which accommodates the curiosities of non-native and aphasic speech. Parallel analytic and holistic processing strategies are the proposed mechanism which reconciles, on the one hand, our capacity for understanding and producing novel constructions using grammatical knowledge and small lexical units, and on the other, our use of prefabricated material which, though less flexible, also requires less processing.