What can governments and people do to keep a language from going extinct?

The aboriginal peoples here in British Columbia are faced with a threat of losing their native languages. This problem is not unique to this part of the world and affects others (such Polynesia and Africa). How should the governing bodies of the aboriginal, provincial (state), and federal jurisdictions react to such a threat? There are more than 20 of these languages here in BC. Should the solution involve focusing on the majority languages? Is there a way to keep all of the languages alive? Is there a utilitarian aspect to the question (i.e. if there is no need for the languages, there is no need to prevent their dissapearance)?

See this map for a visual of the distribution of aboroginal languages in BC.