Khmer Krom ("Lower Khmer") are the indigenous Khmer people of the Mekong Delta (Kampuchea Krom)—now southern Vietnam. Population: ~1.3–8M (estimates vary). They are the descendants of the Khmer Empire's southern territories, annexed by Vietnam in the 17th–19th centuries.
Khmer Krom dialect — mutually intelligible with Standard Khmer (Cambodia) and Northern Khmer (Thailand/Laos). Differences: vocabulary (Vietnamese loanwords), pronunciation (more tones, vowel shifts), some grammar. Written in Khmer script. Taught in some pagoda schools; suppressed in public Vietnamese schools.
Land loss, assimilation pressure, religious restrictions, limited mother-tongue education, statelessness for some. NGOs (KKF, MIRO) advocate internationally.