The Assimil method for teaching foreign languages is through the listening of audio CDs and the reading of an accompanying book, one side native language, one side foreign language. This method is focused on learning whole sentences, for an organic learning of the grammar. It begins with a long passive phase of only reading and listening, and eventually adds active exercises. Most books contain around 100 lessons, with the active phase starting on Lesson 50. The word Assimil comes from assimilation.