Computer (Sprachunterricht) ; Computer (language teaching) ; CALL; E-learning; Mobile-assisted language learning; MALL ; Second language acquisition (language teaching) ; Zweitspracherwerb (Unterricht) ; Foreign language teaching ; DaF; Deutsch als Zweitsprache; German as a second language; DaZ; German as a foreign language ; Indogermanisch; Indo-European languages ; German