You need to download the ISO corresponding to the original Windows language, that is before adding any language packs. Then use that to upgrade to Windows 10. If you need a different language, then you can add the corresponding language pack after Windows 10 installation is complete and activated. All the languages ISO are here and each ISO supports both Home and Pro, so depending on your current Windows 7 version it will upgrade it to 10 Home or 10 Pro. All you need to know is if your current version is 32-bit or 64-bit to download the correct ISO and of course the original (installer) language. If you are not sure which is the original language, you can detect it by creating a new shortcut and pasting this code:
Then double-click to execute it.
%systemroot%\system32\WindowsPowerShell\v1.0\powershell.exe -noexit [CultureInfo]::InstalledUICulture