DaF; Deutsch als Zweitsprache; German as a second language; DaZ; German as a foreign language ; Interference (pragm.) ; Pragmatische Kompetenz; Pragmatic competence; Communicative competence ; E-Mail; Voice mail; Chat; Computer-mediated communication ; Bitte; Request ; Zweitspracherwerb (Textproduktion) ; Second language acquisition (text production) ; Text production (second language acquisition) ; Transfer (second language acquisition) ; Transfer (Zweitspracherwerb) ; Cross-linguistic influence (second language acquisition) ; Interference (second language acquisition) ; German