History of linguistics (19th century) ; History of linguistics (20th century) ; Second language acquisition (language teaching) ; Zweitspracherwerb (Unterricht) ; Foreign language teaching ; Glottodidaktik; Lehrforschung; Pädagogische Linguistik; Pedagogical linguistics; Language teaching research ; Wortschatz (Sprachunterricht) ; Lernwortschatz; Vocabulary teaching ; Semantization (second language acquisition) ; Processability theory; Language comprehension (second language acquisition)