I just can't stop laughing when you say Hmong people call it "nab vam" and thai is "naab vaam"....actually thai call it "nam wan"...hmong white call it "nab vam" and hmong green call it "naab vaam"..
Zoua Her "nab vam" is Lao word w/ Hmong pronunciation. (Lus nplog suab Hmoob). Lao word is written as "ນ້ຳຫວານ" and pronounced as "Nam Van". "nab vam" in Thai is called "ลอดช่อง Lod Chong".