My mothers family is from N ga and we are of Cherokee descent.
Very many people claim Cherokee ancestry for 2 reasons, because they were considered to be one of the "civilized" (read good) tribes. Also, to speak to the idea that the Cherokees "sure got around"... they were one of the largest nations in the Southeast. When they started to be forced out of the mountains, several decided to pretend they were white, it was a survival move. After all, Indians could not own land, make any legal moves, or own arms (even for hunting).
The Cherokees and The Creeks were indeed two seperate nations. The Creek nations were in Georgia, Alambama, and North Florida. If you want to find out more about the Creek confederacy and what was lost visit Moundville one day in Alabama.
Both also had their own "alphabets" of sorts. The Cherokee Syllabry was written down because the US govt insisted to be civilized the nations had to live in houses, go to church, and read and write. Sequoya came up with the syllabry and The People learned it right away. They were able to communicate with each other in print in this way. Fat lot of good that did, they found gold in the Ga mountains, rounded everyone up, and made them WALK to their new "home" in Oklahoma.
However, there was a written language before this time, it just was not in the form of a phoenitic alphabet. It is important to remember that for most Indian nations the men and women who were most opposed to ceding lands to the whites were the educational and spiritual leaders, and these people were often times killed immediately so that they could not incite others to stay true to their old ways. When these important people were removed from the community, and incredible amount of cultural knowledge was lost. If you combine this with the fact that those who were left were either expected to become "Civilized", or they took off to live in hiding, it is amazing that any of the old ways have survived. Many of the the Cherokee nation's important documents (that are thousands of years old) were taken England, taken there by tricky traders.
If you want to see a really good and realistic Indian movie watch Smoke Signals by Sherman Alexie. If you want a good book read Bury my Heart at Wounded Knee or anything by Sherman Alexie.