DaF; Deutsch als Zweitsprache; German as a second language; DaZ; German as a foreign language ; Slip of the tongue ; Spracherwerb und neurologische Entwicklung; Language acquisition and neurological development; Sprache und Denken (Ontogenese) ; Language and thought (ontogenesis) ; Cognitive development; Language acquisition and cognitive development ; Zweitspracherwerb (Textproduktion) ; Second language acquisition (text production) ; Text production (second language acquisition) ; German