Simplify the following text for a Grade 6 native English-speaking person.
Original: Composers of the 20th century variously composed Ã tudes related to the old tradition ( GyÃ rgy Ligeti ) , Ã tudes that required wholly unorthodox technique ( John Cage ) , and Ã tudes that required unusually facile technique .
Simplified: Franz Liszt also wrote some very difficult Ã tudes . These two composers ' Ã tudes are known for being not only good for training but beautiful .