Recent important sociocultural changes, such as the expansion of mass media, have profoundly changed language interaction, especially between teenagers. This project aims to investigate how the Spanish teen language has changed over the past two decades. Concretely, the project has four main objectives. First, it will investigate the speed of language change by monitoring phenomena mostly operating at two different levels, namely the lexicon (including slang words, taboo words, discourse markers, and borrowings) and syntax (mostly phenomena of anacoluthon), at two different points in time, i.e. at the onset of the 21st century and at the beginning of the third decade. This comparison will reveal whether there is a difference in speed between lexical and syntactic change. Second, from a sociolinguistic perspective, the project analyzes which gender or which social class is the most innovative and leads language change. In a third stage, it investigates whether teenagers are rightly defined in the literature as leaders of language change. Finally, it examines the phenomenon of age-grading and the applicability of the apparent-time method. In order to accomplish these goals, the project combines corpus analyses with experimental data.