This thesis focus on teaching Portuguese as a second language to deaf people under a socio-interactional approach to discourse. The study analyses fundamental aspects that appear in the process of teaching/learning Portuguese, in its written form, in a school named Centro Educacional Pilar Velazquez. This school proposes Bilingual Education to deaf people. This work aims at serving as a basis tothose teaching professionals involved in the universe of deafness. We raise some significant theoretical issues: the Brazilian Sign Language (LIBRAS) as the legitimate language of the deaf comunity, their first language; deafness under an anthropological point of view; reflections on the social meaning of written language and its implications regarding the world surrounding deaf people; the orientation of Portuguese when it is viewed as a second language. From these pillars, we have analysed deaf students´s compositions, enlightening and pointing to a genuine - although often not identified - process of learning written language. Our research intends to explicit how deaf people can be regarded as totally capable of developping their potentialities, under an interactional perspective of discourse and by means of the progress shown in their written work.