Languages I never knew existed

My grandfather's driver at the office drives me to university sometimes. We never really talked, until yesterday. One the way to uni he got a call and then I found him uttering words that I culdn't comprehend. A language I've never heard or known before. When he hung up I just couldn't stay silent, curiousty was getting the better of me. "What's the language that you were just talking?" I asked. "It's kenzy," he replied "that's our language in el Nouba where I come from" (el nouba is a place in upper Egypt). "So is that language common?" he told me that it wasn't and that different tribes have different language "Not all Nubians understand themselves"
He started recounting stories from his childhood on how kids made fun of him when he talked, he thought everyone understood that language. He told me he was living at the borders of Sudan, his family had to move after the high dam was built. "The new generation do not know the language," he said "My children don't know how to speak the language. When I talk to my wife infront of them they ask us to talk arabic."

And here I am thinking that alll egyptians talk arabic. Naturally! It's so great to see how diverse people are even within your own borders.I always knew there were tribes and I also knew that not all egyptians are like the cairenes (not that all cairenes are alike), but I had no idea that there's a completely different language here. Not a dialact.