The Wiley Blackwell Companion to Diachronic and Historical Linguistics is an unrivaled resource that explores the mechanisms underlying linguistic evolution. Bridging the gap between theoretical models and empirical research, this comprehensive work connects linguistics with allied disciplines such as psychology, anthropology, sociology, and biology, and provides an enriched understanding of how language interacts with human society and cognition. Contributions from more than 150 leading scholars cover an unparalleled range of key topics, from phonetics and syntax to semantics, pragmatics, and beyond. Spanning five volumes, this work presents detailed case studies from a variety of language families, including underrepresented and non-verbal languages such as sign languages, to demonstrate key elements of theory and practice in diachronic and historical linguistics. By examining the interaction of linguistic systems with societal and environmental factors, this landmark work offers a robust framework for investigating the dynamics of language variation and historical development. The Wiley Blackwell Companion to Diachronic and Historical Linguistics is an indispensable reference for students, researchers, and practitioners in fields intersecting with language evolution, development, and change.