DaF; Deutsch als Zweitsprache; German as a second language; DaZ; German as a foreign language ; Case study (psycholing.) ; Syntactic development; Morphological development; Morphologie (Spracherwerb) ; Syntax (Spracherwerb) ; Grammatical development ; Second language acquisition (psycholing.) ; Gender ; Agreement (gramm.) ; Anti-agreement; Grammatical agreement ; Verb syntax ; German