Most of these languages are not written because they are not spoken vocaly, but localisation to these languages is possible using videos or images; some more formal writing systems are being developed but are still not very used and known as much as adaptation of written languages for people with visual handicaps (most often based on simplified transliteration systems).
Many sign languages also include a gestual transliteration of a common alphabet used to write non-sign languages in order to spell some names (before an abbreviating gesture is then conventionaly agreed between speakers for faster designation in further sign speech).
