Usage-based theories have stressed the importance of input for language learning both in and outside the classroom. When large amounts of input are available, learning gains can be rapid and large. However, the actual learning processes driving L2 development remain to be addressed. Throughout this project, I will look into L2 English speaking and writing development of young, adolescent learners both at the group level and the individual level. An approach which has foregrounded the learning process is complex dynamic systems theory (CDST). When considering the individual learner, I will also investigate the data from a CDST-perspective. I will study L2 English development in two time periods: one long-term study (across secondary school) and one intensive longitudinal study investigating ‘real-time’ development (one-year study). The project will focus on several aspects of the learning process: - First, I will look into the role of internal and external resources in L2 English language development. - A second issue under investigation is the possibility of discerning ergodic groups. - Third, I will investigate the shape of the learning curve for several aspects of language development both in groups and individuals. - The final focus of the project will be on the development of speaking and writing skills relative to each other. With this longitudinal investigation I wish to contribute to our understanding of the L2 language learning process.