Sociophonetics is the multifaceted subfield of linguistics in which phonetics, phonology and sociolinguistics interact. To understand the key questions addressed in sociophonetics, a firm grasp of articulatory and acoustic phonetics is required, together with an understanding of the workings of phonology and an appreciation of sociolinguistic variation, including how subtle phonetic differences can index a range of speaker identities. This book takes an integrated approach in examining issues of phonetics, phonology and sociolinguistics in unison. Assuming little prior knowledge of linguistics, the book begins with a consideration of how English varies, geographically and socially, before introducing the technical terminology and theoretical concepts of auditory and acoustic phonetics. An examination of phonology follows, investigating, in particular, what 'a phonology' is, and what kind of information is stored there. A crucial component of the book is an examination of how phonological variation can be represented in cognition, and how such variation impacts upon linguistic theory. The book also engages with the principles of language change, and examines how sociophonetics can benefit 'applied' fields such as speech technology and forensic speech science. Throughout the book, copious illustration is provided using data from both standard and non-standard varieties of English from Britain, the USA, Australia and beyond. Written in a lively, accessible style and aimed at undergraduate students of phonetics, phonology and sociolinguistics, the book provides the necessary background to allow readers to engage with the sociophonetic literature and the confidence to embark on research of their own. Subjects covered include: *Exploring social and geographical variation in English *The sounds of 'English': production, perception, variation *Looking at sounds: introducing acoustic phonetics *English phonological systems: what are they and how do they vary? *Modelling sound change: splits & mergers, convergence & divergence, lexical diffusion, the role of word-frequency in sound change *Phonological variation and cognition: what do speakers know about the sounds of their language? *Using sociophonetics: speech therapy, speech technology, speech forensics *Doing sociophonetics: approaches, methodologies, and ethics.