English as a second language; ESL; TESOL ; Wortschatz (Sprachunterricht) ; Lernwortschatz; Vocabulary teaching ; Metalinguistic awareness; Phonologische Bewusstheit; Phonological awareness; Focus on form (language teaching) ; Sprachbewusstsein; Linguistic awareness ; Segmentation (morph.) ; Zweitspracherwerb (lex.) ; Second language acquisition (lex.) ; Vocabulary (second language acquisition) ; English ; Japanese