Sociophonetics is a privileged domain for the investigation of language variation and change. By combining theoretical reflections and sophisticated techniques of analysis – both phonetic and statistical – it is possible to extrapolate the role of individual factors (socio-cultural, physiological, communicative-interactional, etc.) in the multidimensional space of speech variation. This book investigates the fundamental relationship between speech variation and the social background of speakers from articulatory, acoustic, dialectological, and conversational perspectives, thus breaking new ground with respect to classical variationist and dialectological studies. Specialists from a broad range of disciplines – including phonetics, phonology, sociolinguistics, psycholinguistics, and cognitive linguistics – will find innovative suggestions for multiple approaches to language variation. Although presuming some basic knowledge of experimental phonetics and sociolinguistics, the book is addressed to all readers with an interest in speech and language variation mechanisms in social interaction.