A recent article on CNN discussed Hawaiian Sign Language, a language still used by only about 40 people, most of whom are elderly. Researchers are working now to document this language before it's too late. According to the article, roughly 80% of HSL signs and the HSL grammar are distinct from ASL, making it its own language, rather than a dialect of ASL.
KITV News also covered the story, along with demonstrations of the differences in signs between HSL and ASL:
A college student in Hawaii also made a video to teach seven common signs used by most Hawaiian people (deaf or not):