What is "native american"? The different tribes of "native Americans" all speak different languages. Which one(s) would interest you? And why should these people write Josph differently? They will write Josph as Josph, probably.
And lastly, if you ask a question here, please expect the answer here as well. If the answer goes directly to you by e-mail, nobody else could profit from the answer - not very sensible.
Rene www.AboutNames.ch