The volume gives an account of two psycholinguistic studies capturing and comparing judgments by German and English native speakers on the decomposability of English idioms. To explain the findings, a model of dual idiom representation is formulated, taking account not only of the lexical but also of the conceptual level and able to image differences and commonalities in the L1 and L2 lexicon. The book integrates linguistic, psycholinguistic and cognitive aspects of idioms.