What is localization QA? ISO 17100, LQA scoring, and error taxonomies

"Good translation" is easy to claim and hard to prove. Localization QA is how you turn quality from an opinion into a measurable, repeatable process — the difference between hoping content reads well and knowing it does.

The ISO foundations

Two standards anchor professional practice:

• ISO 17100 — requirements for translation services: translator qualifications, a mandatory independent revision step, and project record-keeping.
• ISO 18587 — requirements for the post-editing of machine-translation output.

Aligning to these principles means quality is built into the workflow, not bolted on at the end.

Layered review

A reliable process separates roles so no one checks their own work:

1. Translation by a qualified, in-country linguist
2. Revision by a second independent linguist (bilingual review against the source)
3. Review / QA for terminology, formatting, and in-context correctness

LQA scoring and error taxonomies

LQA (Language Quality Assurance) makes quality numeric. Reviewers evaluate a sample against a defined error taxonomy — categories like accuracy, terminology, language/grammar, style, and locale conventions — each weighted by severity (minor, major, critical). That produces a score you can track over time and across vendors.

The point isn't to punish; it's to see patterns. If "terminology" errors spike, your termbase needs work. If "style" issues recur, the brief needs tightening.

Terminology and consistency

QA and terminology reinforce each other. A maintained termbase and translation memory prevent whole classes of errors before review even starts, so QA time goes to nuance instead of re-checking the same words.

Why it matters at scale

With one language, you can eyeball quality. Across 20+ languages and continuous releases, only a measurable process keeps quality stable — and gives you evidence when stakeholders ask "how do we know it's good?"

At Localyn, ISO-aligned review, independent LQA scoring, and terminology control are part of every project by default. See how we protect quality and data or request a quote.