Gradually as they drove along they became quieter, their singing ceased, and they talked in undertones.
"Liza of Lambeth"
W. Somerset Maugham
The Bishop followed to the window at the other end of the room, where the two men stood and talked in undertones.
"The Shepherd of the North"
Richard Aumerle Maher
It was notable that the talk was confined to groups, and was, at first, entirely spasmodic in character, and muttered in undertones as if the speakers were suspicious of their fellow-guests.
"Night and Day"
Virginia Woolf