There you are, sitting in a doctor’s office with a patient and his interpreter. Since you don’t speak the LEP patient’s language, how can you ensure that the interpreter is doing his job properly? On some level, you might not be able to tell for sure, but there are markers that will give you clues.  Interpreters should at all times act in a capable and ethical manner. Based on this criteria, you should be able to identify key signs.

1. Dress.  The interpreter should always dress appropriately for his assignment. If it’s in the courtroom, it might signify a suit and tie; in a medical setting it might be nice slacks and nice leisure shirt. No professional interpreter should ever be seen in jeans or sweats. If the interpreter’s attire leads you to confuse him with a family member, red flags and sirens should be going off in your head!
2. Punctual.  If an interpreter is to act in a manner befitting the dignity of the vocation, he should arrive early to appointments. I know this is really basic, but no professional interpreter is going to arrive, bumbling in late except on very rare occasions.  If they are panting, their head is probably not in the game. I would question their accuracy.
3. Preparation.  Interpreters should ask about the nature of the assignment and review relevant terminology. Face it, we are human, we can’t possibly remember every word.  Take this test in English, if English is your native language.  No professional interpreter feels comfortable diving into an unfamiliar assignment without studying key terminology. Overconfident, incompetent bilingual individuals will most likely try to wing it. Isn’t that scary? At times, circumstances dictate that skilled interpreters proceed, relying on knowledge and experience.  As a rule, research is paramount.
4. Honesty.  Trained interpreters are honest about credentials. No professional interpreter will say he is certified if he is not! Many persons say they are certified, but there is a big difference from obtaining a certificate of course completion and an accredited national or state certification.  Also, if an interpreter is not familiar with terminology in a specific field, he should admit it. Many medical interpreters are not skilled in legal terminology and vice versa.
5. Disclose skill limitation. Just as interpreters need to be honest about credentials, if they don’t comprehend a word or phrase, they need to admit their unfamiliarity and request clarification before continuing. No professional interpreter will guess on words and bluff his way! If you are dealing with technical words, you should expect the interpreter to clarify things occasionally.
6. Admit mistakes. Certified interpreters quickly acknowledge misinterpretations and correct them as soon as they realize them. No professional interpreter will hide a mistake, stay quiet or blame others! People who are prone to errors and conceal them hate interpreting in front of other interpreters. Why do you think would that be?
7. Proper Working Conditions.  Two (2) hours is the maximum for a proficient, consecutive interpreter to work and assure the integrity of the proceeding.  Simultaneous interpreting and court trials require a team and alternate every twenty (20) minutes. Career interpreters will not work under conditions that will compromise their accuracy and reputation. No professional interpreter will work beyond his capacity without speaking up for help. Can you really be confident in someone whose can no longer recognize his mistakes?
8. Respect. Professional interpreters respect coworkers and do not gossip about them.

Many of the issues deal with experience and of itself not necessarily the specific act of interpreting. However, they are great indicators as to an interpreter’s qualifications. They can guide you on establishing or continuing a working relationship with them.  If a lack of expertise is obvious, it would be reasonable to conclude that other serious ethical issues exist.