We would like to use the English language during the installation process.
After that, we want to be able to add another language.
We tried that by selecting English in the installation stage and add the user's language
after the installation completed.
The results were not acceptable: a big mix of English and the user's language within the GUI of Ubuntu itself and its applications.
Basically, what is the best way to use English during the installation process, and another language after the installation completed, regardless of the exact user language?