Using an interpreter during a deposition doesn't have to be painful! As a trained professional interpreter, I have the skills to manage communication without becoming involved, even in confrontational settings or when dealing with witnesses with little education or understanding of the system in the US.
In an interpreted deposition, it's important that the interpreter have experience working with attorneys and court reporters. Remembering to face the reporter when interpreting and prompting the witness to spell any foreign names are simple ideas, but well-meaning bilinguals who are just 'helping out' can't remember or don't know the importance of such things in the first place. It's definitely worth the money to hire a professional.
I offer interpreting services between Mandarin Chinese, Spanish and English. In addition to my language expertise, I also add value with my understanding of the cultures of people who speak these languages. My formal training in interpretation allows me to perform rapid and accurate sight translations of written documents when necessary.