When using a WordPress translation function, e.g. __(), you need to use a hardcoded string (not a variable).
Make Your Plugin Translatable
As we watch the number of non-English WordPress installations grow faster than English installations, the value of making your plugin “translation ready” grows as well. In order to make your plugin translatable (this is also know as Internationalization or I18n), there are three things you need to do. 1. Use Translation Functions Whenever you use […]