They are doing a rather large push to use the language in everyday things and movies is one of those things. If the next generation learns it at a young age it will be preserved. Language is an important part of any culture, one of the most basic building blocks to understand what is important.
note: to those wondering about modern terms - the language isn't dead and new terms are created. This is sometimes done by adding words together (the Dakota word for automobile is long and painful) or adding a suffix / prefix (well, computer for an English example).