This research examines the development of African American English (AAE) from childhood through adolescence and its potential impact on literacy acquisition and school achievement based on a unique, longitudinal database of 70 African American adolescents from low- and middle-income families. The study empirically examines different paths of change in the use of AAE during childhood and adolescence and how these trajectories are linked to selected family, peer, and school factors. Dynamic patterns of language change include the stable use or non-use of AAE through childhood and adolescence, the decline in the use of AAE over childhood and into adolescence, and a curvilinear trajectory in which AAE variants intensify in early adolescence after a period of decline or stability during the early elementary school years. The research further examines how the use of AAE shifts in formal and informal situational contexts through childhood and adolescence, and the longitudinal associations between youth’s AAE use and reading achievement during the elementary, middle, and high school years. Language samples collected from early childhood through adolescence with examiners, mothers, and peers will be coded for use of features of African American language and the presence of code switching in varying situations. These data will then be used together with school achivement, family, and indivudal data to examine the relationship of African American Emglish and school achievement.