Résumé
Our communication addresses the issue "Teaching mathematics in diverse language contexts". In an on-going research, we investigate the effect of learning mathematics in French as a second language on the apprenticeship of logical concepts at the transition between secondary and tertiary level focusing here on negation that Ben Kilani (2005) attested to be problematic in the bilingual Tunisian context. The present study concerns Cameroon, and among the great amount of languages, the Ewondo. We first present the context in Cameroon; then we give some results of an inquiry in France showing strong difficulties with negation at the secondary-tertiary transition, and we present an example of the logical complexity that could occur in the case of proof by contraposition. Finally, we present the methodology of a study in progress, whose results will be available for the conference.