Article révisé par les pairs
Résumé : This article relates the development of conventional time in 120 Belgian children from 5 to 9 years (i.e. those which attend classes going of the 3rd nursery school to the 3rd primary year) through the linguistic tools they have to express metric time and the fitment of durations of several chronometric units (minute, hour, day, week…). The author studies the variations of the statute of the language according to moments' of development by using the vygotskian distinction between “daily or spontaneous” and “scientific or school” concepts. The results show that the children provide different answers according to their school level and highlight several developmental phases between the use of qualitative answers and the construction of the conventional meaning of the chronometric concepts. This study also approaches the cognition-language problematic and the general question of the relationship between concepts and cultural (temporal and linguistic) tools. Key words: concept of duration, cognition-language problematic, linguistic tools.