How do I change the default language of the Matomo UI for all user accounts?

By default, Matomo user interface may appear in English for all users who login to Matomo Analytics. Each user can choose their preferred language in their User Settings. But what if you want to change it for all users at once?

You can easily change and set a new default language for the Matomo user interface. To change the default language of Matomo, edit your config/config.ini.php file and add a new line under your [General] section:

default_language = de

This example sets the default language to German. Here is the list of supported language codes.