The neanderthal represents a very advanced, extinct ape, basically the most advanced member of the same family as gorillas and chimpanzees. We are simply not a part of that family and are not related to it other than via similar design in the same way that Ford and Chevy models might be called "related".
Neanderthal DNA is typically described as about halfway between ours and that of a chimpanzee and it's highly likely that, like the great apes, the neanderthal might never have had voluntary control over breathing, which is the only reason that chimps and gorillas cannot be taught to speak English.
Not correct. They are the same species as we are, Homo Sapiens. We're Homo Sapiens Sapiens and they were Homo Sapiens Neanderthalis