Excerpt from an Sify News article:

Karen Emmorey, a professor of speech language at San Diego State University, suggests language is universal and doesn’t depend on whether people use their voices or their hands to talk.

Broca’s area, related to speech production, and Wernicke’s area, associated with comprehending speech, were supposed to be the two centers in the brain associated with verbal communication.

Earlier, it was assumed that these areas might be particular to speaking, because they are located spatially near areas that are connected to moving the vocal chords, and to the auditory cortex, which is used to hear sounds.

However, researchers found no difference in the brain when they tested 29 deaf native ASL signers and 64 hearing native English speakers.

“It suggests the brain is organized for language, not for speech.”