mumble

含糊地说；抿着嘴嚼英释中释vto say something too quietly or not clearly enough, so that other people cannot understand you

含糊的话；咕噜英释中释nMumble is also a noun

1 He bumped into someone and mumbled an apology..他撞到一个人，咕哝着道了歉。

2 Stop mumbling!.别嘟嘟囔囔的！

3 He could hear the low mumble of Navarro's voice..他能听到纳瓦罗的低声咕哝。