What happens when a site has custom content types installed? Are the correct language strings loaded from the plugin language files?

This does indeed not support 3rd party extensions.
A working solution would be to load all smart search plugin language files (maybe only the .sys.ini ones) and then put the string into those files.

On a sidenote: This PR misses the strings for "News Feed" and "Web Link".

thanks @Bakual
so i close here. But i think it needs work.

A working solution would be to load all smart search plugin language files (maybe only the .sys.ini ones) and then put the string into those files.

hmm sorry i don't know how to do.

The issue should remain open as it still needs fixing, even if this PR does not fix it (entirely).

I have reopen the issue now

hmm sorry i don't know how to do.

@zero-24 To get all smart search plugins you probably can use something like JPluginHelper::getPlugin('finder'). I did not test this but from looking at the code this could help I think.
From there loading language files should be quite simple. See http://docs.joomla.org/Loading_extra_language_files

I get this by adding in models/statistics

            $lang       = JFactory::getLanguage();
    $plugins = JPluginHelper::getPlugin('finder');

    foreach ($plugins as $plugin)
    {
            $lang->load('plg_finder_'.$plugin->name.'.sys', JPATH_ADMINISTRATOR, null, false, true)
        ||  $lang->load('plg_finder_'.$plugin->name.'.sys', JPATH_PLUGINS.'/finder/'.$plugin->name, null, false, true);
    }

See: #2613

i don't know that it work?

I simplified the code above