Just a note that both Language Log and languagehat have entries about poor court interpreting and its effects for the defendant. Bill Poser in Language Log talks about people who can speak two languages but don’t know anything about interpreting, and the fact that they may abridge.
bq. Interpreters may be highly qualified, or they may be the bailiff’s sister who took a little Spanish in high school. No one really knows how often this leads to miscarriages of justice, in part because it is very difficult to appeal on these grounds because appellate courts normally consider only the written record of the trial, and the written record contains only the English translation of the testimony, not what was actually said.
Poser compares Canada and the US, but I fear there is nowhere in the world you could be guaranteed a good interpreter. In Germany, there are sworn interpreters, but not for all languages, and the judges don’t always call sworn interpreters (and, dare I whisper it, not even all sworn interpreters are perfect). The thing that worries me most is the inability of some judges and presumably of most people to understand what interpreting involves.
Steve at languagehat picks up the point about the difficulty of appeal:
bq. This strikes me as a serious problem, and it seems to me that trial records should include a taped record of foreign-language testimony so that if there is a complaint about the translation it can be checked. Otherwise, what’s to prevent an ignorant or malicious interpreter from completely distorting, or even inventing, testimony?
He asks what the situation is in other countries. Bill Poser says in all common-law countries appeals can be based only on the written record. I feel I should know the answer to this. I think the written record is only a big deal in the USA. However, I don’t know how far one can appeal against misinterpretation. Btw, don’t miss the comments at languagehat.