This document discusses several topics related to language contact, borrowing, maintenance, shift, and death. It defines key terms like borrowing, language maintenance, and language shift. It also identifies several factors that can influence language shift, such as demographic, attitude/value, economic, social/political factors. Finally, it discusses different types of language death like gradual, sudden, radical, and bottom-to-top death and identifies several causes of rapid language loss and endangerment on a global scale, including natural/environmental causes, political/military causes, social causes, language policy causes, cultural/religious causes, and linguistic causes.