expression
faint voice; barely audible voice
Idiomatic expression likening a very quiet, weak voice to the buzzing of a mosquito. Often used when someone speaks so softly they can hardly be heard.
彼は蚊の囁くような声で「助けて」と言った。
He said 'Help me' in a voice as faint as a mosquito's buzz.
A set phrase composed of 蚊 (mosquito), の (possessive particle), 囁く (to whisper), ような (like), and 声 (voice). The exact origin is uncertain, but it is a conventional simile for a very faint voice.