Intelligent CALL (ICALL) adds methods from Artificial Intelligence (AI) to explicitly model learners and the target language, to analyze the language that learners produce as well as learning materials. This chapter contributes to a better understanding of how ICALL can promote second language (L2) acquisition and how it can also serve as an effective research tool to investigate instructed L2 acquisition. It illustrates how ICALL systems enable second language acquisition (SLA) researchers to obtain ecologically valid insights into the interaction of a substantial number of parameters that research on aptitude-treatment interactions has identified as important for learning. The chapter argues that ICALL systems provide a unique opportunity for SLA research given that they support large-scale studies of learning in authentic education contexts and the use of learning analytics to explore and conduct fine-grained analyses of learning processes and outcomes.