Right now there is no weapon trader; rather there's a man whose shack holds three weapons you can just take if you want.
The Blacksmith can be found circling a large red and white mushroom, which will spawn beyond the yellow Fog Giant- the one with eyestalks and Signy's Ride in its mouth.
As for a Chinese translation, I cannot speak Chinese at all barring one or two words I've picked up, so I can't help you there- although I do agree that multilingual translations would help this game reach a wider audience.