An interesting knife from the Southeast Asian peninsula

[Sajen]

I came across this interesting knife from the Southeast Asian peninsula, an educated guess from a member here says that it most probably came from the Northern Cambodia to Southern Laos region from one of the many hill tribe groups over there.
When someone is able to tell me more, please add your comment but other comments are welcome as well. The wood from the handle and scabbard shows a great glossy patination, sadly there is a chip broken away at one of the scabbard halfs and a piece cut away from the back scabbard half. The collar is from casted brass. Blade is still very sharp.
36 cm inside scabbard, 28,2 cm without, blade 18 cm, 9 mm thick at the spine behind the handle.