The aim of this article is to call attention to the fact that the existence of sign languages like German Sign Language is in danger. I would like to point out the factors that led to this development and to outline its extent. Firstly, I will give a very short introduction to sign language. In (2.), I will present the factors that led to the endangerment of sign languages: there are prejudices against the speakers (paternalism und discrimination, also with respect to public life), and reaction to this is personal withdrawal and social dissociation. In addition, there is a medicalisation of the speakers, a bias concerning the concurrent acquisition of a spoken and a signed language, a degradation of the language itself and deficiency of institutional support of the language as well as a lack of knowledge about the culture and its products. In (3.) I will try to evaluate these factors by referring to the sociolinguistic concept of vitality (see Giles, Bourhis/Taylor 1977) and will conclude with a calculation of the danger that German Sign Language will cease to exist in the future. It will be demonstrated that German Sign Language is an atypical example for an endangered language. The main reason for this estimation is the fact that there are also many young speakers, as well as the observation that all of the speakers are strongly trying to maintain their language and use it as often as they can. However, the analysis of DGS allows considering some recommendations for the preservation of languages in general.