Hello,
Thank you for using Microsoft products and posting to the community.
Based on your descriptions, it seems that the system accounts used for displaying the Windows Spotlight screen is using Thai.
To check so, please press Windows+R, enter "intl.cpl", go to the "Administrative" tab, and check whether "Welcome screen" is in English. If not, check the "Welcome screen and system accounts" checkbox below, confirm and reboot. Check whether the Windows Spotlight screen is still using Thai.
Please feel free to let me know if you have any further updates, thanks.
Best Regards,
Johann - MSFT | Microsoft Community Support Specialist