The present work lies within the scope of sociolinguistics. It is set to describe and examine lexical variation in youth language including the motives which may affect language change or more precisely dialect change at the level of vocabulary in Tlemcen speech community. As variation and change are conceived as the outcome of various motivations, the study aims at presenting the concepts related to them on the one hand, and at dealing with the description of the situation in Algeria from a historical and a sociolinguistic perspective on the other. In addition to that, it attempts to shed light on the reasons that make the youth use a vocabulary that is different from the one of adults which thus may lead to language change.