I have no idea ????

[Andrew]

It's a mak, used by various peoples across continental SEA. At one time a battlefield weapon (see Mark's site as recommended by JT), I suspect these are now primarily agricultural tools.

I've seen fairly well-made and ornate examples (one was offered by Oriental Arms at Timonium last year--perhaps the owner will post pictures), but the ones I have are somewhat crude, but quite effective.