Before the commencement of interpreter duties, an interpreter appointed under this subchapter shall take an oath or make an affirmation on the record that the interpreter will make a true interpretation to the person who is deaf in the manner that the person who is deaf understands and that the interpreter will repeat the statements of the person who is deaf to the court in the spoken English language to the best of the interpreter's skill and judgment and in accordance with the code of professional conduct for administrative proceeding interpreters for persons who are deaf.