Towards a typology of situations of language contacts. A typology of situations with interactions between native and allophone speakers or between bilingual speakers is built up on the basis of the incidence of trans-codic marks, by crossing of two dimensions: unilingual/bilingual and endolingual/exolingual - an exchange being exolingual when the difference of repertories of the participants plays a constituent role in the interaction. This typology is evaluated, and discussed in relation with the other approaches of language contacts.Une typologie des situations d'interaction entre locuteurs natifs et allophones ou entre bilingues est construite sur la base de l'incidence des mar- ques transcodiques, par le croisement de deux dimensions :...