RIO does not control the spell checking of web browsers, this will be an Microsoft Edge or operating system issue.
Open Microsoft Edge.
Click the three dotted button in the top right corner.
Click the Settings option.
On the left side of the new window, Click Languages.
On this new page you can change the language displayed and the spelling correction.
There are subheadings for each of these sections with Languages at the top of the new page and Writing Assistance below.
There are drop down arrows that reveal the button to toggle which preferred language you want to spell check.