Unfortunately, there is no switch language button to change your language. Therefore, If you are using TurboTax Online Software, you should log out then log in to this link below to use the English version.

https://ww1.2020.turbotaxonline.intuit.ca/signout

If you are using TurboTax CD/Download, uninstall TurboTax, then reinstall the English version that can be downloaded from here: https://turbotax.community.intuit.ca/replies/3001486

Thank you for choosing TurboTax. 

I just downloaded the English version of TurboTax Premier by mistake. Can I get the French version instead?? What do I have to do to get it changed ?