She used to be a wonderful singer, but her vocal chords were burnt by an oppressive government as a punishment for speaking out.
Mattaeo thinks her “new voice” is still amazing, but Angie still refuses to sing in front of anybody and she cries when she sings as her voice cracks.
Angie, like Mataeo and most of the rest of the young main characters, was separated from her mother as a baby and made to live in poverty before finding her mother after Mataeo’s parents reuinted them.
To add insult to injury, Angie’s family are famous opera singers and every generation they are proud to be singers. This makes Angie feel very outcasted. Her mother still loves her, but her grandmother not so much.