Nuclear family was the place where original language was created. This is also the place where language is learned.
As family grows, nuclear family becomes extended family, then clan, then tribe, then nation. All along the same language is used between members of the this growing family to keep communication going. Family is preserved through communication and cooperation and for that you need a common language. If all these people are linked genetically, through father to son inheritance, I believe that we can talk about genetic languages. R1a languages, R1b languages, I2a languages…