Language-Aware Spellchecking in Teams

Multilingual Dexterity When Composing Teams Messages

Office 365 notification MC217362 of June 26 noted that language-aware spell checking would appear in the Teams Windows desktop client (but not for GCC tenants) with deployment to finish by the end of July. This change is documented as Microsoft 365 roadmap item 65446, which says “Users who write different messages in different languages will now see spellchecking relevant to the language they use when typing a message in the Microsoft Teams desktop app.” It’s another step forward to making Teams an app that works well in international settings.

Communicate Bilingually

The idea is simple: users often switch languages to better communicate with co-workers. Their PC is configured for a specific language and keyboard layout, which Teams uses to figure out the default language for spell checking. For instance, my PC is configured to use English, but sometimes I might need to chat with someone in French. Teams monitors text as it is entered, and if the client detects enough instances of a specific language, it prompts to allow the user to confirm that the switch should continue. As you can see, I’m asked “are you writing in French now” (Figure 1).

Teams concludes that it should switch to French for spell checking
Figure 1: Teams concludes that it should switch to French for spell checking

Microsoft’s text is a little confusing about the prompt shown to users. MC217362 says “a user might see a compose notification UI letting them confirm/revert the switch.” The conditional tone of the statement means that it isn’t very clear as what will happen. Some experiments show that after Teams detects that a conversation is in a specific language, it switches spell check to that language and displays the prompt.

The Need for User Communication

Experience with the feature is mixed. Some report that users are confused (after all, it’s a change in client behavior) while some like the opportunity to have their text checked. Like most changes of this nature, it’s best to have some up-front communication with users to make sure that they’re not surprised.

Apart from the ability to turn spell checking on or off in Teams client settings, neither users nor administrators can control how automatic switching of spell check languages works.

Client-Side Spell Checking

Microsoft emphasizes that this is a client-side feature and that no data is transmitted back for server-side translation as is the case when Teams uses Microsoft Translator to translates chat and channel conversations when users read text. Because spell checking is done on the client, a dependency probably exists on some components that aren’t available on the Mac and Linux desktop clients, which is why these clients aren’t supported.

Some Improvement in Spell Checking Still Needed

Microsoft says that the change is “an improvement to existing spellchecking in Teams Desktop.” I guess that’s true, but Teams still lags when it comes to spell checking because it doesn’t allow users to add words to the custom Office dictionary. This means that any custom words learned in Word and the other Office apps show up as misspellings in Teams.

This is a small but irritating restriction that’s been around since Teams was introduced. At least, it is to those who care about proofing. I hear rumblings that improvements are coming, and it would be nice if Teams supported the Office custom dictionary and allowed new words to be added. We live in hope.


This is detail that probably won’t affect the success of an Office 365 deployment. But it’s nice to know, which is why we consider stuff like this as we put together the Office 365 for IT Pros eBook.

15 Replies to “Language-Aware Spellchecking in Teams”

  1. The information I’m missing here is: how safe is it to ignore the prompt? In your example, if you don’t click “Yes” to the question about typing in French, does it then keep spell checking in English, since you’ve not confirmed the change? Or does it spell check in French, since you’re not reverting its assumption?

    My biggest problem with the prompt is that I’ve found it tends to reappear very often during a conversation, and when my hands are on the keyboard, not on the mouse, it’s a hassle to click it each time it wants information.

  2. Is this language aware spell check a server side update or does it need an update of the Windows 10 Teams client? I’m waiting for this feature since a long time ago but I still don’t see it working at the 1.3.00.24755 (64 bits) version of that client. Thanks for the information about this topic.

    1. I believe it is a client-side feature. Maybe sign out and sign back in again. That sometimes fixes Teams issues.

  3. [quote]Because spell checking is done on the client, a dependency probably exists on some components that aren’t available on the Mac and Linux desktop clients, which is why these clients aren’t supported.[/quote]

    Somehow I’m baffled by reading this. Did you check that?
    Linux (and I expect Mac as well) has had multiple client-side spell checkers for years, maybe even before Windows had one. One example is hunspell, which on my Linux distro has around 150 addon language packages.
    It’s quite trivial to use hunspell, so it’s a matter of actually starting to use an existing spellchecker instead of -maybe?- trying to re-invent the wheel. Oh btw, Teams is written using Electron, right? There’s: https://www.npmjs.com/package/electron-hunspell. So..
    However, could there be some license incompatibility issue at play here? It wouldn’t surprise me.

    1. The dependency is no reflection on Linux. It’s more of a dependency on the components used by Teams on Windows. It seems like the devs haven’t selected an equivalent for Mac and Linux. No doubt this will happen over time.

  4. After last update on my Teams, this resource disappeared!!! Anyone knows if this resource was phased out or if it is an optional from now?

      1. I did it zillion times… Global IT from my company have also accessed my PC many times and no one is able to fix it. It seems that really is discontinued by Teams app…

  5. This feature disappeared!!! not able to use it anymore, I handle teams in Brazil, Spain and US and now teams is not able to detect it anymore, do you know what happened?

      1. As I mentioned before. At least I tried many times this resource you mentioned but no success at all… If I need a check spelling I need to change the check spell manually before sending the message… for me, no sense! mainly because this same resource is still running fine on Outlook…

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