I'm writing a Word document and it's not being spell checked

Common causes are:

• The text or document is set to Do not check spelling or grammar.
• The wrong proofing language is applied to the text.
• The language needed for proofing is not enabled or its proofing tools are unavailable.
• A misspelled word was added to a custom dictionary, so Word ignores it.
• In some Word versions, settings such as Detect language automatically or keyboard/language matching can affect proofing behavior.

A practical fix path in Word is:

1. Press Ctrl+A to select the whole document.
2. Go to Review > Language > Set Proofing Language.
3. Make sure Do not check spelling or grammar is cleared.
4. Select the correct language for the document.
5. If spell check still misses words, verify the language is enabled in Office and that the correct dictionary is being used.
6. Run a manual check from Review > Spelling & Grammar.

If only certain paragraphs are affected, select just those paragraphs and repeat Review > Language > Set Proofing Language for that text.

If Word still skips obvious misspellings, check whether the word was added to a custom dictionary and remove it if necessary.

References:

• Troubleshoot checking spelling and grammar in multiple languages
• Check grammar, spelling, and more in Word
• Check spelling and grammar in Office
• Spellcheck Not Working and Frustrating - Microsoft Q&A
• Spelling correction - Microsoft Q&A