People use “interpretation” and “translation” interchangeably in everyday speech. In the language-services industry they describe two distinct disciplines, with different credentials, pricing models, and quality controls.
The simplest rule
Interpretation is spoken. Translation is written. An interpreter renders speech from one language to another in real time, on the phone, on video, or in person. A translator renders a written document from one language to another, working from a written source.
Interpretation
Interpretation happens live. The interpreter listens to the source language and immediately renders meaning into the target language. There is no editing pass. Two industry-standard modes exist:
- Simultaneous: the interpreter speaks at the same time as the source speaker, with a few seconds of lag. Used for conferences, courtrooms, and broadcast.
- Consecutive: the source speaker pauses every few sentences and the interpreter then renders that segment. Used for medical visits, depositions, and one-on-one meetings.
Interpretation can be delivered over the phone (OPI), via video (VRI), or on-site. Medical interpreters typically hold credentials from the National Board of Certification for Medical Interpreters (NBCMI) or the Certification Commission for Healthcare Interpreters (CCHI). Court interpreters are state-certified or, for federal court, hold the FCICE credential. ASL interpreters are RID-certified.
Pricing is per minute (OPI/VRI) or per hour with a two-hour minimum (on-site). The deliverable is the encounter itself, not a written artifact.
Translation
Translation works from written source to written target. The translator has time to research terminology, consult subject- matter experts, and pass the work through editing and proofreading steps before delivery. Quality controls include:
- Translation memory: tools that reuse previously approved translations of recurring phrases, improving consistency.
- Glossaries and termbases: agreed-upon terminology for client-specific terms, drugs, products, statutes, etc.
- Back translation: a second translator renders the translation back into the source language so the client can compare meaning. Standard for clinical-trial materials.
- Certified translation: a signed statement of accuracy required by USCIS, courts, and many government agencies.
Translation is billed per word (most common) or per page. Translators typically hold ATA certification in their language pair, plus subject-matter credentials for specialized fields (legal, medical, pharmaceutical, technical).
When you need both
Most healthcare and government organizations need both. A hospital may need an interpreter on the phone for triage and a translated copy of the discharge instructions for the patient to take home. A school district may need an interpreter at an IEP meeting and a translated copy of the IEP document. A court may need a state-certified court interpreter for a hearing and a certified translation of exhibits.
Quick comparison
| Dimension | Interpretation | Translation |
|---|---|---|
| Medium | Spoken | Written |
| Delivery | Real-time (phone, video, on-site) | Asynchronous, with editing |
| Billing | Per minute or per hour | Per word (sometimes per page) |
| Common credentials | NBCMI, CCHI, RID, state-court, FCICE | ATA, subject-matter expertise |
| Quality controls | Live monitoring, post-call review | Editing, proofing, back translation |
| Deliverable | The encounter itself | Translated document with optional Certificate of Accuracy |
Which do you need?
If the encounter is happening now and the parties need to speak to each other, you need interpretation. If you have a written document to convert, you need translation. If you need both — which most organizations do — pick a vendor that does both well under a single contract.