Hello!
You can try to Reset Downloaded Languages.
To clear language-related glitches:
Go to Settings > General > iPhone Storage.
Check if any downloaded apps or files have Spanish language packs.
Delete and reinstall the apps to force them to use Turkish as the default.
Also, If you’re using a VPN, it could maybe be the cause of this issue.
If your VPN is set to a Spanish-speaking country, it might be tricking your iPhone into thinking you’re in that region. This could cause app downloads and settings to default to Spanish instead of Turkish, even though your language and region settings on the device are set to Turkish.
Hope this helps!