Certified interpreters abide by a Code of Ethics that not only establishes the parameters for their conduct in and out of the courtroom, but also provides all end-users and stakeholders with vital information as to what can and cannot be expected of a professional interpreter.
Foremost in the Code of Ethics is the interpreter's role as a neutral officer of the court. The interpreter in a legal setting has the immovable responsibility of conveying to non-English speaking or Limited English Proficient individuals everything that is being said in a legal proceeding in their own language, without omitting or adding anything. Interpreters make it possible for these individuals to be fully present in the same way they would be if there were no language barrier. It is also the court interpreter's role to convey witness testimony in languages other than English for the record as if those witnesses were testifying in English, whether such testimony is being offered by the prosecution or the defense. Professional court interpreters remain impartial under any and all circumstances, never taking sides.
Source: NAJIT.ORG