DaF; Deutsch als Zweitsprache; German as a second language; DaZ; German as a foreign language ; Lexikometrie; Lexicometry; Automated Similarity Judgment Program; ASJP; Lexicostatistics ; Stylistics (mathematical) ; Vorkommenshäufigkeit (Stilistik) ; Frequency (stylistics) ; Mathematical stylistics ; Metalinguistic awareness; Phonologische Bewusstheit; Phonological awareness; Focus on form (language teaching) ; Sprachbewusstsein; Linguistic awareness ; Speech production (psycholing.) ; Error analysis (language acquisition) ; Second language acquisition (psycholing.) ; German