Hello I too have had come across this frustrating issue where as I installed a new system and created a new user account, After reboot I have notices that the input language for the login and password is no longer in English but a different language that I have added.
I have found a solution, in these few easy steps without any use of terminal or reinstallation of OS,
All that needs to be done is as follows:
1. Goto System Prefs. and open Users&Groups.
2. Login Options.
3.Make sure you have marked "show input menu in login window".
4.When you are at the login window on the top right you will see the input language,
First choose the language you wish to remove then click again it and you will see a drop down menu, Then choose the "Remove current input source"


Hope this solves the problem to anyone with this issue.
😉