Quiver is a verb that means to shake slightly, usually it is compared to a shiver or a trembling. A quiver can be the act of quivering or a container for an archer’s arrows.
The adverb form for the verb is quiveringly. The adjective form is quivery, but this is rare and should be used with caution. There is a slight preference for this adjective form outside the United States.
Quaver is a verb that means to shake one’s voice slightly, so that the sounds produced undulate or falter. This is especially when one is feeling fear or worry. It is as if one’s voice is shivering or trembling. It also has a noun form for the action of quavering.
The adverb form is quaveringly, and the adjective form is quavery.
In short, quiver is the shaking of an object or person and quaver is the shaking of one’s voice.
Interestingly, quaver is used most often correctly outside the United States. Whereas within the United States, its more likely to read the erroneous quiver in one’s voice.
For months, I’ve been fretting for a sick friend, and just when he was back eating cheeseburgers and being a general pain in the tookus once again, our adjustable mortgage jumped 0.75 percentage point — a quiver, a caress. [Los Angeles Times]
Dan Willson, the Edinburgh-based singer-songwriter behind Withered Hand, is quiveringly diffident between songs, but powerfully engaged during them. [The Guardian]
And as he talks about his wife having other health problems now, noting that “we’re not alone in this”, there is even the faintest quaver in Tebbit’s voice. [Irish Times]
He still loves noisy, overloaded mixes; he still has an imagination that mixes the cosmic and the macabre, flinging around lyrics like “Perfect-looking humanoids we’re all that remains/Identically insane, our rotting little brains,” in his high, quavery voice. [The New York Times]