On January 17, 2017, USCIS published new guidelines on the use of translators at USCIS interviews. See https://www.uscis.gov/sites/default/files/USCIS/Laws/Memoranda/2017/2017-17-1-RoleUseInterpreters-PM-602-0125-1.pdf.
The policy sets forth requirements for the interpreter’s qualifications including fluency, competency and impartiality. The policy prohibits the use of an interpreter who is under the age of 18, who is a witness in the case, who is biased, or who is the applicant’s representative/attorney. There is a new form, Form G-1256, that must be completed and signed by the interpreter and the interviewee.