Some theories on the development of language include the idea that spoken language has its origins in gestural routines. Gestural language combined with phonetic ability to move language to speech. See this recent article for evidence that supports such theories. Link and excerpt below.
Gestures or Words? To the Brain, It's the Same
By Jamie Talan, HealthDay Reporter - Tue Feb 23, 8:50 PM PST
At least that's what evolutionary language theorists would have people believe. Spoken language, they contend, is unique to the human brain, and that sets people apart from other primates.
But new research, co-authored by Patrick J. Gannon, a physical anthropologist and chairman of basic science education at Hofstra University School of Medicine, suggests that the brain doesn't really care how it receives information. A waving hand up in the air to summon a waiter for "check please" works just fine. The language areas of the brain -- the highly evolved frontal and temporal lobes -- process simple gestures with the same snippet of tissue that's used to hear the prose of Shakespeare, according to Gannon's study.
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