Lavi (Lawi; autonym: Swoeng or səlwəŋ) is a Mon–Khmer language of the Bahnaric branch spoken in Sekong Province, Laos. Chazée (1999:95) estimates the population at 500, while the 1995 Laotian census places the Lavi population at 538.The Lavi language was discovered by Thai linguist Therapan L-Thongkum in the late 1990s. Within the West Bahnaric branch, it is the most divergent language (Sidwell 2003).