Although all over the world deaf people face the same problems acquiring spoken and written language, detailed empirical studies are missing. The aim of this study was a grammatical analysis o faxes written by deaf adults. 236 faxes were selected from two Australian institutions. Analysis dealt with lexicon, morphology and syntax. Results show that there are three competence group, which differ in a statistically significant way. Group 1 consists of deaf subjects whi have fairly complete knowledge of written German; members of group 2 know the more basic rules and show less syntactic complexity in their texts while members of group 3 use holophrases, lack differentiation of word categories and show problems with serialisation.