The Proto-Algonquian language is the an ancestor of all Algonquian languages. It is thought to have been spoken around 2,500 to 3,000 years ago.
References
↑Goddard, Ives (1978). "Central Algonquian Languages". In Trigger, Bruce G.; William C. Sturtevant (eds.). Handbook of North American Indians: Northeast. Vol.15. Washington, D.C.: Smithsonian Institution. pp.583–587. ISBN978-0-16-004575-2.