The readings are on'yomi readings. You've learned them both already (you learned 手's on'yomi reading with word 投手), so you should be able to read this like a singer sings with a bunch of cashews かしゅ in their mouth. FAST AND LOUD!
My mother had a large influence in my becoming a singer.
That singer got quite a tan, didn't she?
I used to be a singer when I was kid. Well, who am I kidding, I’m still a singer now.