This volume enlists more than two dozen experts in the fields of linguistics, psycholinguistics, neurology, and cognitive psychology to investigate the concept of entrenchment—the ongoing reorganization and adaptation of communicative knowledge. Entrenchment posits that our linguistic knowledge is continuously refreshed and reorganized under the influence of social interactions. Contributors examine the psychological foundations of linguistic entrenchment processes, and the role of entrenchment in first-language acquisition, second language learning, and language attrition. Critical views of entrenchment and some of its premises and implications are discussed from the perspective of dynamic complexity theory and radical embodied cognitive science.