natural voice; untrained voice
Refers to a person's raw, unprocessed voice without amplification, editing, or vocal training. Often contrasted with a trained singing voice or a recorded voice.
Her natural voice is very beautiful.
I spoke in my natural voice without a microphone.
Compound of 生 (なま, 'raw, unprocessed') and 声 (こえ, 'voice'). The reading なまごえ follows standard rendaku voicing of the second element.