This reference provides an overall view of the pronunciation and vowel systems of the dialects of the USA and Canada. The Atlas redefines the regional dialects of American English and draws new boundaries reflecting the speech of the mid 1990s. The Atlas findings show a dramatic and increasing divergence of English dialects as vowels in different regions are rotated in opposite directions by the Northern Cities Shift, the Southern Shift, and the Canadian shift, and other sweeping changes that are affecting the North American continent as a whole. The 26 chapters trace the influence of geographic and social factors by the multivariate analysis of population size, gender, age, occupation and ethnicity. An accompanying CD-ROM provides the full data base with 100,000 measurements, maps of individual vowel systems, and extended sound samples of all dialects.