Origins of human language

[kerry]

I woke up early this morning and was thinking about the widespread appeal of speaking in tongues in our world and why it began and remained for a long time in the working classes. This in turn got me thinking about the general origins of human language and the transition from a non-speaking species to a speaking species. It dawned on me that human language must have arisen from a mutated set of identical twins because language is inherently social and conveys no evolutionary benefit to a solitary speaker. Identical twins have been known to invent languages between them. I've read virtually nothing on the evolutionary origins of spoken language. Has anyone here? Does anyone know if this hypothesis has been examined?

Do other primate species have twins?