There is a new study comparing modern human and Neanderthal brain cases. Link: http://news.sciencemag.org/sciencenow/2010/11/neandertal-brains-developed-more.html?etoc
The study concludes that Neanderthal did not have the same development regarding language and complex social networks. They speculate that they were less good at language and trade.
Regarding trade, this is supported in the book “Desolate landscapes” that concludes that Neanderthal seemed to use raw materials from their surroundings while modern humans seem to have traded a lot more as evidenced by long distance movements of raw materials. So, this notion is supported by archeology.
Regarding language, it could very well be that Neanderthal had differences in language and language acquisition. It is quite possible that their language use were related to imitiation of animal sounds rather than social learning of language. As previously posted, autistics do not acquire language the same way as neurotypicals do. Small isolated groups also do not lend themselves to the same type of language use that is typical for modern humans.
It is evident that these findings fits perfectly well into the Neanderthal theory. It is in the areas of language and social networks that Aspies lack adaptations that neurotypicals have. Neanderthals instead had a different set of social adaptations for living in small groups.