Research projects ; Linguistic institutions ; DGS; German Sign Language ; Gesture communication ; Schichtenspezifischer Sprachgebrauch; Barrierefreiheit (Kommunikationsforschung) ; Communication access; Communication barrier; Language barrier ; Barrierefreiheit; Communication access; Communication barrier; Exklusion (Soziolinguistik) ; Exclusion (sociolinguistics) ; No Child Left Behind Act; Inclusion/Exclusion (sociolinguistics)