"ü and u" how can I distinguish that? words

My favorite pop singer I like pop singer that Rihanna,Coldplay,and Kate perry. 我喜歡的歌手有蕾哈娜、酷玩樂團以及凱蒂佩芮。 Their style of song is unique. 他們的歌曲風格都是獨特的。 by the way they are also the most popular of the world singers 而且他們也是全世界最流行的歌手。

First notebook entry: Introducing myself Hello, everyone my name is Aki.