Input Processing is a theoretical framework on which the pedagogical paradigm called Processing Instruction is predicated. In this book, new data on the acquisition of Italian and Modern Standard Arabic are presented and analyzed within this framework. Each study in the book explores how input processing strategies affect the acquisition of a particular linguistic feature and/or structure in the two languages. The studies use both offline (e.g., sentence and discourse-level tasks) and online tests (e.g., eye-tracking) to measure the effects of this instructional training.