When learning a L2 (foreign language), vocabulary difficulties can concern a variety of different characteristics of a lexical unit (LU), which we name PVPs (Problematic Vocabulary Points). Our study focuses on the possibilities a synthetic world (Second Life) may offer in supporting learners with PVPs. We analyse the potentials of this environment during a course which took place in February 2011 and which adopted a CLIL (Content and Language Integrated Learning) approach. During this course, student groups, accompanied by architecture tutors and language tutors, created virtual objects in collaboration using their L2 (two groups using English and two groups using French) and participated in reflective sessions about this process. The analysis presented in this study reveals that i) needs related to vocabulary were varied and were expressed in Second Life in the audio for the greater part, ii) tutors' support consisted mostly of recasts of PVPs concerning meaning iii) these pedagogical regulations helped solve PVPs during the interaction, in particular via the audio mode.
