Before being appointed Professor at the Collège de France, Luigi Rizzi was Professor of Linguistics at the University of Siena and the University of Geneva, where he led the ERC project " Syntactic Cartography and Locality in Adult Grammar and Language Acquisition ". His work focuses on invariance and variation in natural languages, syntactic structure mapping, syntactic locality and language acquisition. This year's lectures and seminars will focus on the basic elements and operations of language. What are the " atoms " of language, the elements from which the rich linguistic combinatorics is structured ? What are the elementary operations that define syntactic calculation ? How are these basic ingredients acquired by the child learning the language ?