I go along with the SE Asia attribution on this, and note the incongruity of the white and brass metalwork. This seems interpretive of European officers sabres in the hilt reflecting the ribbed grips as well as the birdhead form pommel/backstrap (of course not suggesting that the pommel in any particular way represents the head of a bird
I would imagine this to date mid to latter 19th c. and am inclined to agree more with Thailand. The vegetal decoration does seem to favor acanthus, which of course was popular on the neoclassic theme often seen on the blade decoration on European officers sabres, in this case probably British and fashioned after the M1796 sabres . I have seen British officers M1796 sabres that are indeed quite small as well. The smaller size I think were for easier wear in formal events.
Best regards,
Jim