English as a second language; ESL; TESOL ; Komplexes System; Complex system; Emergenztheorie; Emergence (theory of) ; Systems theory ; Self-organization ; Reformulation; Recast (function in discourse) ; Paraphrase (function in discourse) ; Classroom communication; Instructional communication ; Second language acquisition (pragm.) ; Zweitspracherwerb (pragm.) ; Interactionist hypothesis (second language acquisition) ; Conversational analysis (second language acquisition) ; English