J.K. Chambers is Professor of Linguistics at the University of Toronto. He is the author of Sociolinguistic Theory: Linguistic Variation and its Social Significance, Revised Edition (Wiley-Blackwell, 2009) and Dialectology, Second Edition (with P. Trudgill, 1998), as well as numerous other books and scores of articles. He works extensively as a forensic consultant and maintains a parallel vocation in jazz criticism, including a volume on the bebop pianist Richard Twardzik (2008) and a prize-winning biography of Miles Davis, Milestones: The Music and Times of Miles Davis (1998). Natalie Schilling is Professor of Linguistics at Georgetown University. She is the author of American English: Dialects and Variation, Third Edition (with W. Wolfram, Wiley-Blackwell, 2016) and Sociolinguistic Fieldwork (2013). An expert in language variation and change in American English, she conducts workshops on sociolinguistics and forensic linguistics for an array of audiences within and beyond academia, and is a noted consultant in both these fields. Among her works for general audiences is English in America: A Linguistic History, an audio-video lecture series for The Great Courses (2016).