Spell check not working on Microsoft Teams desktop

Dear jharmon , hope you are doing well.

I had the same problem - i.e. spell check is not working in teams. I deleted the content of the C:\Users\appdata\roaming\Microsoft\teams\dictionaries folder, restarted Teams, but the issue persisted.

This is how I solved the problem: 

# I opened the log.txt file located in "C:\Users\[user]\AppData\Roaming\Microsoft\Teams" folder.

# I found the following error "error -- spellCheckerService initialization failed: Message: es-419 is not a valid language code"

Which means es-49 (Spanish - Latin America) is not supported by the spellCheckerService.

# I removed Spanish - Latin America configuration from the preferred languages in Windows (I am using Windows 10): Windows Settings -> Time & Language -> Language -> Preferred Languages

# Restarted the computer (just to be on the safe side)

# Logged in on Teams --> and it worked.

Note: English-US is the default language in my computer. Yet, Teams tried to set the Spell Check service to Spanish Latin America for some reason.

Note2: In your case, the spellCheckerService may be trying to initialize using a different language. 

Hope it helps,

-F