The use of synthetic worlds in language teaching/learning is still controversial in France. Yet, international research (Jarmon et al.; Wigham and Chanier) has demonstrated the educational value of such innovating devices which enable learners to be creative and facilitate learning. We have chosen to check the pedagogical value of those serious video games and have carried out experimentation with second year students in Business management and trade. For this, we have used the multiplayer multidimensional synthetic world Second Life. In this article, we shall study the strengths of this device when it comes to acquiring and/or consolidating the linguistic and general competences of learners of ESP. Our analysis will rely upon the paradigm of enaction coined by Francisco Varela and we shall suggest that the creation of avatars in virtual worlds can facilitate the cognitive development of English learners.