I'v done some more search...

some of indian tribe talking exactly like that and I never knew that, my bad!

p.s. thanks HDinHB (ID) in Ubisoft forums that guide me in this matter

Ubisoft is great Game Co. and Assassins's Creed games have great story... BUT how they can't specify the difference between accent of Native American and Indian from India ?! they done research and work with Pros? how they can done a big mistake like this?? Native Americans in Assassin's Creed III talk whit Indian Accent form INDIA COUNTRY !!!