How the brain processes sign language. Over 70 million deaf people use sign languages as their preferred communication form. Although they access similar brain structures as spoken languages, it hasn't been identified the brain regions that process both forms of language equally. Scientists have now discovered that Broca's area in the left hemisphere, central for spoken languages, is also crucial for sign languages. This is where the grammar and meaning are processed, regardless of whether it is spoken or signed language. Source 8e.