This collection of articles presents two central perspectives in the current sociolinguistic study of youth language, both of which are comparatively new to sociolinguistics. One tendency is the study of the effects of new technology on the linguistic behaviors of late modern, particularly urban, youth, including mobile telephones and computers. The other tendency is the study of the effects of increasing diversity in linguistic resources available in late modern societies, again particularly evident among urban youth. Both of these sets of effects are richly documented and analyzed in the contributions of this volume which presents research and data from China, Croatia, Turkey, Denmark, Germany, and a host of other places.