A lot of people think interpreters are “support staff.”

Commonwealth v. Diaz, a 2020 Pennsylvania Supreme Court case, shows why courts don’t treat it that way.

In Diaz, the issue wasn’t whether the interpreter was polite, punctual, or “good enough.”

It was whether the defendant could understand what was happening and communicate with counsel at critical moments, and whether the absence of interpretation effectively took him out of his own trial.

That’s not a customer service problem. That’s a constitutional problem. (Commonwealth v. Diaz, 226 A.3d 995 (Pa. 2020).)

What happened in Diaz

Miguel Diaz was a Spanish speaker. The record shows he had some functional English, enough for everyday life, but that courtroom language and pressure were different.

On the first day of trial, Diaz did not have a Spanish interpreter.

And that first day was not “administrative.” It included:

argument on pretrial motions
jury selection
opening statements
and testimony from the complaining witness (Diaz, 226 A.3d at 999.)

The next day, the defense raised that Diaz was uncomfortable and needed simultaneous interpretation moving forward, and an interpreter was provided for the remainder of trial. (Diaz, 226 A.3d at 999.)

Years later, on post-conviction review, the courts had to confront what that first day meant: if Diaz couldn’t understand what was happening, he couldn’t consult with counsel in real time, and he couldn’t truly participate in his defense.

Why the court treated this as more than a “mistake”

Here’s the heart of Diaz:

The Pennsylvania Supreme Court held that when the absence of a needed interpreter at a critical stage obstructs the defendant’s ability to communicate with counsel, courts can apply United States v. Cronic, meaning the defendant does not need to prove specific prejudice the way they would under the usual Strickland test. (Diaz, 226 A.3d at 997, 1011.)

This is an important distinction for attorneys:

It’s not “show me exactly how the outcome would have changed.” It’s “this kind of breakdown is so fundamental that the system can’t rely on the result.”

That’s how seriously courts treat language access when it impacts the right to counsel.

“Some English” is not “legal English”

Diaz is also a reality check about how we evaluate fluency.

A client can:

speak basic English
answer conversational questions
appear confident

…and still be completely lost when the language becomes technical, fast, and high-stakes.

In Diaz, the record included expert testimony explaining how stress and the “register” of courtroom English can cause comprehension to collapse for someone who is only partially fluent. (Diaz, 226 A.3d at 1002, 1007.)

This is exactly what experienced professional interpretersrecognize instinctively. Everyday English is one thing. Legal proceedings are another.

And this is where attorneys get exposed, not because anyone did something unethical, but because language gaps don’t announce themselves. They hide behind nods and “yes.”

The Sixth Amendment lens (and why this matters outside the courtroom)

This is the point you made, and it belongs in this blog.

The core of Diaz is the Sixth Amendment right to counsel.

Not “a lawyer exists somewhere in the room,” but the right to meaningfully consult with counsel at critical stages of the case.

Diaz ties the absence of a needed interpreter to something very specific: when a person can’t understand what’s happening well enough to communicate with counsel in real time, the right to counsel is obstructed. (Diaz, 226 A.3d at 997, 1009-1011.)

And that principle doesn’t magically turn off when you walk out of court.

Because the truth is: most “critical communication” happens outside the courtroom:

preparing a client for deposition testimony
reviewing discovery responses
walking through medical records and timelines
settlement authority conversations
mediation prep and caucus strategy
reviewing a declaration or sworn statement line-by-line
making sure the client understands what they’re agreeing to before they sign

When language prevents a client from truly consulting with counsel in these moments, the problem is the same: the representation becomes one-sided. The client becomes passive. And “participation” becomes performative.

That’s why, when the communication is critical, a qualified interpreter isn’t a nice-to-have, it’s the tool that allows counsel to actually function as counsel.

This is where working with an interpretation and translation agency becomes more than convenience. It becomes risk management.

What this means for civil attorneys and organizations who hire interpreters

Unlike criminal trial interpreting (often court-arranged), civil attorneys and organizations frequently do hire their own interpreters, and the stakes can be just as real:

a deposition interpreter in a high-pressure record-making event
legal interpreting services during arbitration and mediation
in person interpretation for sensitive client meetings
virtual interpretation for remote proceedings
simultaneous interpretation when pace and volume demand it

And beyond litigation:

interpreters for a company meeting where legal exposure exists
interpreter services for conference attendees
interpreters for breakout sessions or for a users conference
cross-border matters needing global translation services
document translation that aligns with testimony or sworn filings
legal translation and certified legal translation used in contracts, declarations, and compliance work

This is why attorneys increasingly choose vetted certified interpreters and court certified interpreters through established interpreting companies in California and across the USA. When things go wrong, it’s rarely obvious in the moment. It shows up later, in credibility, in transcripts, and in disputes about what someone “really understood.”

Where Kaplan Interpreting Services fits

Kaplan Interpreting Services provides language support for attorneys, law firms, healthcare and corporate clients across:

legal interpretation and legal interpreting support
legal interpreting services for depositions, mediations, arbitrations, and meetings
court certified interpreters when the matter calls for that level
in person interpretation and virtual interpretation
simultaneous interpretation when speed and volume make it necessary
document translation, legal translation, and certified legal translation
broader translation and interpretation services for complex matters

If you’re coordinating documents, onsite and video interpreting, or you need a quote for a court-certified interpreter for a deposition, our job is to make sure language is not the weak link in an otherwise strong case.

Because Diaz reminds all of us of something simple:

When a person cannot understand what’s happening, they can’t participate, and when they can’t participate, the system can’t pretend the outcome is reliable.

Are you an attorney or law firm where language access protects your client’s rights? When the record matters in depositions, mediations, client meetings, and sworn declarations, we partner with civil and criminal practices nationwide for hand-matched, court-certified interpreters with zero compliance issues. Request firm-level pricing.