Do tracked changes survive translation, or do they get flattened?

They survive. LangTo translates the text inside each insertion and deletion and keeps them as tracked changes, so the redlines come back in the target language and you can still accept or reject each one in Word. Most tools extract plain text and lose the revision markup entirely.

Are comments kept too?

Yes. Comments are translated and kept attached to the text they annotate, alongside the tracked changes — so a reviewer's notes come across, not just the redlines.

Do I need to turn anything on?

No. Preserving tracked changes is the default — a redlined document is kept redlined automatically. Nothing in the file is silently accepted or flattened.

Will the changes still be reviewable in Word after translation?

Yes. Insertions and deletions come back as real tracked changes, so your usual accept/reject review works exactly as before — just in the translated language.

Is this for PDF or Word?

Word (.docx). Tracked changes are a Word feature; a PDF has no revision markup to preserve. If your redlined document is a Word file, this applies; a PDF is translated as editable Word without redlines.

Can I rely on it for a complex contract?

We verified it end to end on a real standard contract — the Common Paper Mutual NDA with insertions, a deletion, and a comment — and every change and the comment came across, still reviewable in Word. As with any translation of a legal document, open the result and check the terms that matter before a live negotiation; the free tier makes that check free to run.

How to Translate a Word Document and Keep Its Tracked Changes (2026)

To translate a Word document without losing its tracked changes, the tool has to translate inside the revision markup — the insertions, the deletions, the comments — and leave them marked. Most don't. They pull the plain text out, translate that, and hand back a document where the redlines are gone: either silently accepted, or flattened into ordinary text with the change history lost.

For a contract under negotiation or a draft out for review, that's not a minor formatting slip — it's the whole point of the document erased. Here's why it happens and how to keep a redlined document redlined through translation.

Why tracked changes disappear in translation

A Word document isn't the text you see — it's the text plus a layer of markup: which words are insertions, which are deletions, who commented where. Tracked changes and comments live in that layer.

The common way to translate a document ignores the layer entirely. The tool extracts a flat stream of text, translates it, and rebuilds a plain document. The insertions and deletions were never carried through, so they can't come back. You get a translation of the accepted version — or worse, a document with content quietly dropped — and the negotiation history is gone.

Keeping tracked changes means translating within the markup, not around it.

How LangTo keeps redlines and comments intact

LangTo translates a Word document inside its structure, so the revision layer survives the trip:

Insertions and deletions stay marked as changes. The text inside each redline is translated, but it comes back as a tracked insertion or deletion — so you can still accept or reject each one in Word, exactly as before.
Comments come across, translated and attached. A reviewer's note stays anchored to the text it was about, in the target language — not stripped, not piled at the end.
It's the default — nothing gets silently accepted. Preserving the revision history is automatic; accepting or flattening changes is destructive, so LangTo never does it on its own. You don't toggle anything.
The rest of the document holds too — footnotes, headers, footers, equations, and hyperlinks stay in place, so a translated draft is still a working document, not a stripped-down copy.

The result is the document you started with — same redlines, same comments, same structure — in another language, ready to keep reviewing.

How to translate a redlined document

Upload the Word file with its tracked changes and comments intact.
Choose the languages — source (or auto-detect) and target.
Add a glossary if terms must land exactly — useful for a contract where defined terms and party names have to stay consistent.
Download the result. It opens in Word with the insertions, deletions, and comments preserved, in the target language.

Then open it in Word and run your normal review — accept, reject, reply to comments — as if the document had never left your hands.

What we verified — and where to look

To confirm this isn't just theory, we ran a real, widely used contract through it end to end: the Common Paper Mutual NDA — an openly licensed standard used by thousands of companies — marked up with insertions, a deletion, and a reviewer comment, translated English to Chinese. Every change came back translated and still marked as a tracked change you can accept or reject; the deletion stayed a deletion, the replacement showed both the struck-out old text and the new; and the reviewer's comment stayed attached to its clause, in Chinese. It's a capability you can run today, not a spec.

A few real boundaries worth knowing:

It's a Word feature. Tracked changes live in .docx; a PDF has no revision markup to keep. A redlined Word file is the right input.
Heavily marked or deeply nested passages deserve a closer look. A paragraph with many overlapping edits is harder than a clean one.
Review the substance, as you would any translation. Open the result in Word, confirm the changes and comments came across, and check the wording of the terms that matter. The free tier makes that check cost nothing.

Why this matters more than a formatting nicety

For most documents, losing formatting is an annoyance. For a document under review, losing the tracked changes destroys the thing that made it worth translating — you can no longer see what was proposed, what was cut, or what a reviewer flagged. Rebuilding that history by hand, in a language you may not read fluently, is exactly the work you were trying to avoid.

Keeping the redlines is what lets a foreign-language draft stay part of the same negotiation, instead of restarting it.

Try it on a document you're reviewing

The honest test is a redlined file you already know. Upload one, translate it, and open the result in Word to see whether the changes and comments held. You get 300 free credits a month with no card, and if a translation fails, the credits are refunded — so the check costs you nothing.