Needs assessment (language teaching) ; GERS; CEFR; Quadro Comune Europeo di Riferimento; Common European Framework of Reference for Languages ; DGS; German Sign Language ; Gebärdensprache (Zweitspracherwerb) ; Sign language (second language acquisition) ; Sign language (language teaching) ; Gebärdensprache (Sprachunterricht) ; Second language acquisition (sign language)