(mumbling) incomprehensibly; while mumbling; mutteringly; murmuringly
彼はむにゃむにゃと夢を語った。
He muttered about his dream incomprehensibly.
朝の会議でむにゃむにゃした。
He mumbled during the morning meeting.
むにゃむにゃと何かをつぶやく。
Muttered something under his breath.