Juan Manuel Hernández-Campoy is Professor in Sociolinguistics at the University of Murcia, Spain, where he teaches undergraduate courses on English Sociolinguistics, Dialectology, and the History of English, as well as sociolinguistic research methods for postgraduate students. His books include Style-Shifting in Public (with J.A. Cutillas-Espinosa, 2012), Diccionario de Sociolingüística (with P. Trudgill, 2007), Metodología de la Investigación Sociolingüística (with M. Almeida, 2005), and Geolingüística (1999).

Juan Camilo Conde-Silvestre is Professor in English Historical Linguistics at the University of Murcia, Spain, where he teaches on the History of the English Language and Research Methods in Language Variation and Change. His books include Sociolinguistica Histórica (2007), Sociolinguistics and the History of English (with J.M. Hernández-Campoy, 2005) and Variation and Linguistic Change in English (with J.M. Hernández-Campoy, 1999).