DaF; Deutsch als Zweitsprache; German as a second language; DaZ; German as a foreign language ; Second language acquisition (psycholing.) ; Transfer (second language acquisition) ; Transfer (Zweitspracherwerb) ; Cross-linguistic influence (second language acquisition) ; Interference (second language acquisition) ; Indefinite article; Definite article; Unbestimmter Artikel; Bestimmter Artikel; Article ; German