Same here . . Windows in Portuguese and I cannot change the language format because it would swap the decimal point with the thousand separator and mess up many things, including all my Excel worksheets.
Could not find a way to remove the aulo-login, so my only choice was to uninstall and reinstall the launcher. (not that bad as I am a new user and have just downloaded it for the first time)
If I understood it right, I will have to click on the globe and change language every time I launch it.
It would be nicer to have the language as an internal engine setting and not inherit it from an OS settings.
[EDIT] - Even choosing English in the login globe, several words still remain in Portuguese (image attached - English in green, Portuguese in yellow).
This is an additional challenge when following the tutorials.