sotto voce

It’s no secret: in our first example sentence, sotto voce functions as an adverb, modifying the verb tell. But sotto voce, which was borrowed into English from the Italian word sottovoce (literally meaning "under the voice"), can also serve as an adjective. That’s the role it plays in our second example sentence. The adverb sense first appeared in English in the 18th century and soon afterward found use in musical directions calling for whispered vocals. The adjective sense came about in the early 19th century.