This volume presents the semiotic and linguistic theory of extended axiomatic functionalism, focusing on its application to linguistic description. The theory is compared with other approaches to semiotics and linguistics, and particularly with the standard version of axiomatic functionalism. An informal account is given of the twin basic components of the theory - the signum ontology and the system ontology. The former provides a set-theoretically based account of the network of relationships between the abstractions of linguistic theory (at whose apex stands the signum), and the phonetic and semantic facts of speech events. The latter deals with the purely abstract level of analysis, and covers roughly the traditional areas of phonology and grammar. A set of postulates, constituting a formal statement of the theory, is provided in an appendix. It is shown that the signum ontology can provide adequate accounts - sometimes in conjunction with interfacing extra-theoretical models - of a range of phenomena from phonetics to pragmatics, including incomplete neutralization, imperfect synonymy, polysemy, idiom, and figures of speech (particularly metaphor). The relationship between core-linguistics and psycholinguistics is considered, and an initial model is developed for the interface between extended axiomatic functionalism, as a sentence-linguistic theory, and text-linguistics. The issues dealt with in this book are not only relevant to extended axiomatic functionalism and indicative of its broad scope, but are also of current interest in linguistics generally; the analyses proposed are considered in the context of existing analyses throughout. Without disguising complexities, the book presents extended axiomatic functionalism in a clear and accessible manner. Wide use is made of figures and cross-referencing, and detailed indices are provided.