@KoiwiGal - Well, the modern cultures probably do have a fair bit in common now, because they were all at a relatively similar level of technology when America was colonized and most of them suffered from similar treatment. I would say they probably have a lot in common with other marginalized groups as well, like the Aborigines in Australia.
It is very important now for them to focus on and celebrate their differences though, particularly with the people who surround them. Language in particular is such a crucial part of culture and it often disappears when surrounded by a larger, dominant group.
Native American history has been so filled with oppression, I hope that different groups can start to thrive again.