 To encourage the growth of the camas plant and maintain a habitat beneficial to deer and elk, the group regularly burned the valley floor to discourage the growth of forests, a common practice among the Kalapuya.The Atfalati spoke the Tualatin-Yamhill (Northern Kalapuya) language, which was one of the three Kalapuyan languages.Prior to contact with white explorers, traders, and missionaries, the Kalapuya population is believed to have numbered as many as 15,000 people.