低声

low voice; undertone; low; hushed; low-pitched; in a low voice; in an undertone

哼唱

hum; croon; sing softly; chant

孩子

child; kid; children; youngster; son; daughter; family; offspring; son or daughter; bairn; sonny; progeny; childish; childlike

入睡

fall asleep; go to sleep; sleep; crash; drop off; doze off; off