reading [something]를 marks the object being read, and 읽는 is the noun-modifying form of 읽다 (“to read”); together, 를 읽는 comes before a noun, as in 카프카를 읽는 날 (“a day when [someone] reads Kafka”).
KO: 언젠가 체코어로 카프카를 읽는 날이 오면 좋겠군요.
EN: I hope that someday a day will come when I can read Kafka in Czech.