Language testing ; English as a second language; ESL; TESOL ; Spracherwerb (Schriftsprache) ; Language acquisition (written language) ; Kindersprache (Schriftsprache) ; Child language (written language) ; Schrifterwerb (psycholing.) ; Written language acquisition (psycholing.) ; Academic achievement; Language and intelligence ; Reading performance ; Sprachverständnis (Lesen) ; Textrezeption (Zweitspracherwerb) ; Text reception (second language acquisition) ; Reading comprehension ; Speech perception (second language acquisition) ; Sprachperzeption (Zweitspracherwerb) ; Speech production/speech perception (second language acquisition) ; English