Legal Recognition

"Sign Language Legislation in the European Union", Wheatley, M., A. Pabsch., Edition II. Brussels, EUD, 2012:

Switzerland, as a country with more than one spoken and signed language, has not officially recognised any of the national sign languages. The Swiss Federal Constitution guarantees freedom of languages, not explicitly mentioning sign language (or any other languages). However, it is understood that this includes the national sign languages. By contrast, the Constitution of the Canton of Zurich explicitly refers to sign language in its article 12:

'The freedom of languages also includes sign language.'
(..)
The Disability Equality Act (.. BehiG) in effect provides for sign language interpreters in official contexts. Article 14(3)a mentions sign language explicitly: The federal government should support measures of the cantons to provide education in sign language.
This sentence is controversial, as it is part of federal legislation and education is usually the responsibility of the cantons.Educational legislation in the individual Cantons does not mention sign language at all and bilingual education/education in sign language is largely not provided for."