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Office Language Doctor

Guide / Microsoft Office

How to fix the wrong proofing language in Word and PowerPoint

When Word or PowerPoint marks correctly written words as spelling errors, there is more than one possible cause. The problem may come from your keyboard or Office settings, but it can also be stored inside the document in paragraphs, styles, slides, notes or other text runs.

Editorial author · CECO LabUpdated · 30/09/2026Word · PowerPoint

01 / Diagnosis

First: identify which problem you actually have

01

It changes in new documents

Check the active Windows keyboard, Office authoring/proofing languages and defaults first. Word can follow the system input context.

02

Only part of one document is wrong

The file may contain different proofing-language metadata in text runs, styles or paragraphs. Pasted content is a common source of mixed settings.

03

Word changes language while you type

Check Detect language automatically and the active keyboard. Automatic detection is not identical across Office apps; PowerPoint does not expose the same automatic-language option.

04

PowerPoint slides and notes disagree

Visible slide text is not the only place language can be stored. Notes, charts, SmartArt and pasted runs may keep different settings.

02 / Office

Manual correction inside Office

For a specific selection, the normal route is Review → Language → Set Proofing Language. Choose the intended language and decide whether automatic detection is appropriate for that document.

  • If the problem returns in brand-new documents, repairing the current file will not fix a keyboard, template or default-language problem.
  • If the document is genuinely multilingual, forcing one language across the whole file can make proofing worse.
  • For long documents, identify the mismatched areas before changing hundreds of text runs.
Microsoft Support: configure or change proofing languages

03 / Document metadata

When the problem is stored inside the document

OOXML formats such as DOCX and PPTX can store proofing language at more than one layer. A text run may inherit language from direct formatting, a paragraph, a style or document defaults. That is why two pieces of text that look identical can behave differently.

Signals that point to mixed document metadata

  • One paragraph is flagged while the next paragraph in the same written language is not.
  • Only the section pasted from another document switches proofing language.
  • Slides look correct but notes, charts or SmartArt use another proofing language.
  • Selecting the whole document and changing language appears to work, yet some fragments still disagree.

04 / Audit

Audit before repair with Office Language Doctor

Office Language Doctor is aimed at the third category: proofing-language metadata stored inside the file. It processes the document locally in the browser, surfaces mismatches and lets you review which fragments to repair before generating a corrected copy.

  • Word OOXML: DOCX, DOCM, DOTX and DOTM.
  • PowerPoint OOXML: PPTX, PPTM, POTX, POTM, PPSX and PPSM.
  • OpenDocument and initial RTF support are also documented on the current technical sheet.
  • Smart Fix is conservative: ambiguous cases should not be treated as safe automatic fixes.
  • It does not replace keyboard configuration, Office language packs or operating-system preferences.
View the Office Language Doctor technical sheetOpen the web app

05 / Checklist

Short checklist

  1. 01

    Check whether the same problem appears in a new document.

  2. 02

    Check the active keyboard and Office proofing languages.

  3. 03

    Select an affected fragment and inspect the proofing language Office reports.

  4. 04

    If only specific areas are wrong, audit the file before forcing a global language.

  5. 05

    Keep the original before any large repair.

06 / Scope

What this guide does not fix

This guide does not assume every language problem is document metadata. If the language changes because of the keyboard layout, a template, Office defaults or automatic detection, fix that cause before repairing files.