Iconicity has become a popular notion in contemporary linguistic research. This book is the first to present a synthesis of the vast amount of scholarship on linguistic iconicity which has been produced in the previous decades, ranging from iconicity in phonology and morpho-syntax to the role of iconicity in language change. An extensive analysis is provided of some basic but nonetheless fundamental questions relating to iconicity in language, including: what is a linguistic sign and how are linguistic signs different from signs in general? What is an iconic sign and how may iconicity be involved in language? How does iconicity pertain to the relation between language and cognition? This book offers a new and comprehensive theoretical framework for iconicity in language. It is argued that the linguistic sign is fundamentally arbitrary, but that iconicity may be involved on a secondary level, adding extra meaning to an utterance.