A language is transmitted extra-genetically. At the same time we know that mothers are their children's first language teachers. That's why you can have a small highly militarized group take over a far larger population and just disappear linguistically and genetically ~ except for a trace here or there.
You have to have females in some number in your own group for your identity as the conqueror to prevail in the eventual mix, and there's always a mix.
Hungarian linguistic researchers are working on it. Their belief is that Hungarian is a creole which derives in part from a cognate language to ancient Sumerian, and that language in turn derives from a cognate to ancient Dravidian core languages. If that's true with Hungarian, it's true with Finnish, and Estonian, and yet it may not be true at all when it comes to the Sa'ami languages.
The next 50 years of study into Ice Age languages should be exciting (if you're into that sort of thing).