How can I output ALL strings from a lang file? I need to output a JSON object containing all of the key/value pairs in either /translations/{myLocale}.php or /craft/plugins/myplugin/translations/{myLocale}.php.

I can't see any way of doing that?

I can see that I can call craft()-&gt;getComponent('messages') but that will retrieve all of Craft's internal translations - I only want the messages I have defined in one of the files above.
You could include the translations file into your controller:

$translationsFile = craft()-&gt;path-&gt;getPluginsPath().'myplugin/translations/de.php';
$translationsArray = include $translationsFile;

$this-&gt;returnJson(array_keys($translationsArray));