Last week we rolled out spellcheck to both Microsoft Edge Canary and Dev (builds 139 and higher), gradually ramping up traffic to 100%. Spellcheck is currently based upon Hunspell.
How does the service work?
The associated dictionaries needed for Hunspell are not shipped with the browser, they are downloaded from a remote server where dictionary files reside and downloaded when needed. As a result, we implemented a download service that one-time downloads the right HunSpell dictionary to enable the local speller. The spellcheck feature does not send keystrokes to a service, keeping your activity private. Currently, 46 languages are being supported.
The default language to start with
You can add a language by navigating to Settings-> Languages-> Add languages and select the language from the list. Once you add the language(s) you want they’ll be added under Check Spelling section as well and each language will have a toggle button to turn it on/off. For the languages where spellcheck is not supported yet, will have a disabled toggle button.