English as a second language; ESL; TESOL ; Textbook analysis ; Pragmatische Kompetenz; Pragmatic competence; Communicative competence ; Discourse marker ; Second language acquisition (pragm.) ; Zweitspracherwerb (pragm.) ; Interactionist hypothesis (second language acquisition) ; Conversational analysis (second language acquisition) ; Lemmata ; Hongkong (engl. Sprache in) ; Hong Kong (English language in) ; English in Hong Kong