The ability to override existing language definitions was added in 5.11+
Customizing Language
To customize language:
- Visit /language/ab_cd/ where ab_cd is the language, like en_us.
- Find _override-example.php and rename it to _override.php
- Add your language overrides by copying the definition from any other language file for this language and pasting it into this file, modifying the language string as desired.
For example, if you want to change a definition found in /language/en_us/users.php, copy the language string like:
$lang['Users.!error.username.empty'] = 'Please enter a username.';
And paste it into /language/en_us/_override.php with your changes like so:
$lang['Users.!error.username.empty'] = 'My custom text here.';