Language File Loading Conventions
If a storefront side plugin creates a new page
It will be able to use language definitions from the following files, which will be automatically loaded:
the main language file
includes/languages/lang.english.phpand the templated version of that file,
includes/languages/english/extra_definitions(and their templated versions)
The page’s own language file,
Language files which are a substring match of the name of the main file - for example,
includes/languages/english/lang.newpage_success.php. Note that this behavior may be disabled for specific files - see substring matching for language files.
If you need to load a language file that’s not loaded by these conventions, follow the instructions in loading a language file.