The Swiss have decided to teach three languages, the local language, a second national language and English, from Primary school on. This should enable communicative encounters between persons from different linguistic backgrounds. An asymmetry between productive and receptive competences should foster the receptive bilingualism in a form sometimes called “Swiss model”: everyone speaks his or her own language and understands the other. But real communicative practices do not match this stereotype fully. This paper analyses the complex dynamics of face to face interaction in some key examples of authentic cross-linguistic communication at work in Switzerland. It shows how native and non-native speakers take mutual profit from all the languages they know. Neither monolingual models nor receptive bilingualism strictu sensu dominate; “mixed” forms of exploiting the respective repertoires emerge. In order to understand this language use, the paper questions the traditional representations of language competence.