Quick answer
Overlapping text after PDF translation almost always means the source file was a scan: it already carries an invisible OCR text layer, and the translation gets added on top of it.
What causes a duplicate text layer in scanned PDFs
Scanning software writes a transparent, machine-readable text layer over the page image so the file becomes searchable. That layer is invisible on screen but is still real text. When such a file is submitted for translation, the translated text is placed over a page that already has text on it, so two layers end up stacked.
How to tell if your PDF has a hidden text layer
- The translated file shows original and translated text overlapping
- Only the original text is visible, while the translation is there but transparent
- Selecting text with the cursor highlights words that are not where you clicked
- The page looks like an image, yet text search still finds words on it
How to fix overlapping text after PDF translation
- Upload the original, digitally generated PDF rather than a scan of it
- Run the scan through our Flatten PDF tool first — flattening merges the page into a single layer and removes the hidden OCR text
- If you only have the scan, translate it as a scanned document so OCR runs once instead of twice
- Check the source file for hidden text layers before submitting a batch
Related tools
Bottom line
Two layers of text is a property of the source PDF, not a translation error. Upload an original PDF, or flatten the scan into a single layer first, and the problem disappears.