It is the ability to make each hand speak in several voices at the same time, with individual strands having their own weight and color.
He smiled as Neena raised her hand to look at the ring, then spoke.
Her thin hands spoke a language of their own.
At the big table in the center of the room, you have to yell through cupped hands to speak to your neighbor.
Instead, many raised their hands and their voices to speak.
The Harlequin said nothing, but his free hand spoke for him.
Vainte came forward then, so close that their hands almost touched, and spoke with great feeling.
The hand which held the paper crumpled it up slightly as Katherine spoke.
He kept one hand on the seat back, spoke as much to himself as to Ship.