Second language acquisition (language teaching) ; Zweitspracherwerb (Unterricht) ; Foreign language teaching ; Feedback (language teaching) ; Rückmeldung (Sprachunterricht) ; Lehrerkommentar; Teacher's comment; Correction (in language teaching) ; Attention (language acquisition) ; Zweitspracherwerb (ungesteuerter) ; Second language acquisition (untutored) ; Natürlicher Zweitspracherwerb; Second language acquisition