YOU SAID:

the bird can only fly when the world isn't round

INTO JAPANESE

世界が丸くないときだけ鳥は飛ぶ

BACK INTO ENGLISH

Birds only fly when the world is not round

INTO JAPANESE

世界が丸くないときだけ鳥は飛ぶ

BACK INTO ENGLISH

Birds only fly when the world is not round