Two distinct problems get called challenging the interpreter. One is a qualification problem: this person may not hold the credential the proceeding requires. The other is an accuracy problem: that specific rendering was wrong. They are raised differently, at different moments, and confusing them is how a deposition turns into an argument instead of a record.
Why an interpreter can be examined at all
California Evidence Code section 750 provides that a person who serves as an interpreter or translator in any action is subject to all the rules of law relating to witnesses. That single sentence is the doctrinal basis for everything in this article. The interpreter is not a piece of equipment or a neutral fixture. They occupy a role the law already knows how to test, which means qualifications can be examined and conflicts must surface.
Section 751(a) supplies the substance of what they have undertaken: the interpreter swears to make a true interpretation to the witness in a language the witness understands, and a true interpretation of the witness's answers into English, using their best skill and judgment. Section 751(d) allows a court-employed interpreter who is certified or registered to file that oath with the clerk, in which case it serves for subsequent proceedings until the appointment is revoked.
The qualification challenge
Raise this before testimony begins. In California you may not have to raise it at all, because the interpreter is required to volunteer the information. Government Code section 68561(h) requires the interpreter at a deposition to state their qualifications including certification or registration number, their oath status, and that the badge and photo identification were presented to both parties.
In practice that statement is frequently not made. When it is missing, the request is short and unremarkable: ask the interpreter to state their qualifications and credential number on the record, and to present the badge. This is not an accusation, it is a statutory step nobody performed, and framing it that way keeps the temperature down.
A sequence that works, in ascending order of seriousness:
- Ask for the name, spelled, and the certification or registration number.
- Ask which language and variety the credential covers.
- Ask whether the oath was administered today or is on file with the court.
- Ask for the badge and photo identification to be presented, as the statute contemplates.
- If the interpreter holds no California credential, ask what qualification is being relied on, and make sure the answer is in the transcript.
The last item matters even if you proceed anyway. Whether the tier was certified, registered, or something else determines whether the fee is recoverable as a cost, which is set out in who pays for the deposition interpreter. A transcript that records the answer protects that position either way.
Conflicts of interest
California Rule of Court 2.890 requires an interpreter to be impartial and to disclose any actual or apparent conflict of interest, and states that any condition interfering with the interpreter's objectivity is a conflict. It gives acquaintance with a party or witness, and an interest in the outcome, as examples. The rule also requires accurate representation of certifications, training and relevant experience, bars disclosure of privileged communications between counsel and client, and prohibits the interpreter from giving legal advice.
In smaller language communities, acquaintance is common rather than exceptional. The right handling is disclosure at the start, on the record, and a decision by the parties. Discovering mid-deposition that the interpreter knows the deponent socially is a far worse position than being told at the outset. Our article on the interpreter code of ethics covers the conduct standards in more detail.
The accuracy challenge
This one is raised in the moment, and the goal is a clean record rather than a victory. The workable protocol:
- State the concern on the record, identifying the specific word or phrase rather than characterising the rendering generally.
- Ask the interpreter to state the rendering again, and to explain the choice if the disagreement is about a term of art.
- Where a check interpreter is present, have the two interpreters confer.
- State the agreed rendering on the record, or state that the disagreement is unresolved and identify both proposed renderings.
- Continue.
What does not work is two interpreters correcting one another in real time, which produces a transcript where the disagreement is preserved and the testimony is not. Nor does saving the objection for later: an accuracy dispute raised after the deposition, with nothing in the record identifying the disputed passage, is close to unarguable.
Mode matters here more than most people expect. Consecutive rendering produces a discrete utterance you can point at and dispute. Simultaneous rendering frequently does not, which is one of the practical reasons sworn testimony is rendered consecutively. That is covered in consecutive or simultaneous interpreting at a deposition.
Check interpreters
Bringing your own interpreter to monitor the rendering is legitimate and, handled well, useful. Two courtesies make it work: say in advance that you are bringing one, and agree the protocol on the record at the start, so an intervention is a stated concern through counsel rather than an interruption from an unidentified voice.
A check interpreter who raises one well-founded issue in a day has earned their fee by preventing a transcript problem. A check interpreter with no protocol who contests renderings continuously will produce a deposition that runs long and a record that is worse than the one you started with.
Sight translation is a separate objection
When a document in another language is handed to a deponent and rendered aloud on the spot, that is sight translation, and it is a different task from interpreting speech. It is slower and more error-prone, because the interpreter is reading and rendering simultaneously with no chance to hear the text first.
Where the exact wording of a document is what the testimony turns on, the appropriate objection is not to the interpreter but to the method: ask that the exhibit be translated in writing and marked, rather than rendered aloud. Evidence Code section 753 addresses translators of writings and provides that the record identify the translator, which is a useful reference when you are arguing for a written translation instead.
After the deposition
Sometimes the problem is only visible on reading the transcript. An answer does not follow the question, a term is rendered inconsistently across the day, or a passage reads as fluent English that the deponent could not plausibly have produced. What is available then depends almost entirely on what went into the record at the time.
Where the credential statement was made, you know who interpreted and at what tier, which is the starting point for anything else. Where a specific rendering was disputed on the record, you have an identified passage rather than a general complaint. Where neither happened, you are asking a court to draw conclusions about an interpretation nobody documented, performed by someone whose qualifications were never established.
Practical steps that preserve the position without escalating prematurely:
- Note the specific transcript pages and lines rather than characterising the whole deposition.
- Have the disputed passages reviewed by an independent qualified interpreter before asserting anything.
- Raise it in correspondence promptly, because delay undercuts the argument that the problem was material.
- Where the deposition was video recorded, the recording contains the original testimony and the rendering, which is frequently more useful than the transcript alone.
That last point is worth building into practice in advance. On a matter where interpreted testimony will be central, video recording the deposition preserves something a transcript cannot, and the marginal cost is small relative to the exposure.
A note on proportion
Most interpreted depositions run without incident, and an attorney who challenges everything will lose credibility long before they gain an advantage. The purpose of knowing this material is not to generate objections. It is that when something genuinely goes wrong, you can put it on the record in two minutes, in a form that is still useful a year later.
Sources
California Evidence Code sections 750, 751, 752, and 753, and California Government Code section 68561, available through California Legislative Information; California Rule of Court 2.890, published by the Judicial Council of California. Verified against the primary sources in July 2026. This article describes procedure and is not legal advice for a specific matter.
AMS interpreters state their credentials on the record as standard and disclose conflicts before an assignment begins. See our deposition interpreting service.