Since this word is made up of a single kanji, it should use the kun'yomi reading. When learning the kanji, you didn't learn that reading, so here's a mnemonic to help you with this word:
Think about a song... but not just any song... think about the utter (うた) song, and make it up right now and sing it out loud. What does the utter song sound like? Why do you love utterances so much that you made a song about them?
But I don’t know Japanese songs very well.
It feels like this isn't just a song, but a secret code too.
"Jason! You made a song for Amanda?" "Ah, this isn’t what it looks like." "Come on! Don’t give me that."