Lehrplan; Syllabus; Curriculum research ; English as a second language; ESL; TESOL ; Dialekt (im Unterricht) ; Dialect (in class) ; Language variation (language teaching) ; Ideologie und Sprache; Ideology and language; Ideology and linguistics; Ideologie und Sprachwissenschaft; Language and ideology ; Periphery (linguistic geography) ; Core/periphery (linguistic geography) ; Three circles model (of world Englishes) ; Center/periphery (linguistic geography) ; English as international medium ; English