Language testing ; Unterrichtsfilm; Audio-visual aids (language teaching) ; Evaluation criterion (language teaching) ; DaF; Deutsch als Zweitsprache; German as a second language; DaZ; German as a foreign language ; Glottodidaktik; Lehrforschung; Pädagogische Linguistik; Pedagogical linguistics; Language teaching research ; Metalinguistic awareness; Phonologische Bewusstheit; Phonological awareness; Focus on form (language teaching) ; Sprachbewusstsein; Linguistic awareness ; Dreisprachige Erziehung; Trilingual education; Multilingual education ; German