What characteristics should an interpreter own ?   I think he should be an expert of everything .   Why is that ?   Because English is nothing but a tool which is used when people may negotiate in international conferences , probe into physics , release some information in a press conferrence , and do anything we can do with language . Therefore , an interpreter has to know some expertise in the field he / she serves as an interpreter . Otherwise he / she can not carry out his / her work smoothly . 