DaF; Deutsch als Zweitsprache; German as a second language; DaZ; German as a foreign language ; Idioms (language teaching) ; Lehrplan; Instructional advice ; Phraseologie; Idioms; Phraseology ; Proverb scholarship ; Lexikometrie; Lexicometry; Automated Similarity Judgment Program; ASJP; Lexicostatistics ; German