At what age should we learn a second language? Which are the intellectual faculties which bilinguism helps to develop? What is the compared efficiency of language learning in childhood and in adulthood? In which case does a person forget a language, particularly a mother tongue? Claude Hagège tells us here that anybody can become perfectly bilingual and how Europe, which is not the continent where the most bilingual people are found, can multiply their number. Indeed, the challenge of bilingualism is at the heart of European union.

C. Hagège, professor at the Collège de France, has published in particular L'Homme de paroles and Le Souffle de la Langue.