As you can see in the video, Joomla users can install and use Joomla in their own language. Sadly, there are still some steps that need to be done in English. Specifically after installing Joomla on the server, users must navigate in English through the Joomla Administration until they find the installer that allows them to add their preferred language package. This represents a language barrier for some users.
There are different solutions:
Solution 1This could be solved by adding a new screen in the step-by-step Joomla installation application. Check the following proposal:
Primarily this option adds a new screen/step in the installation process of Joomla!
The other option to solve the issue could be to add a checkbox in the first screen of the Joomla installation:
What Joomla Installation Application will do if the checkbox is active is explained in the following video: