Using com_finder I can create a search filter and let users specify search by type.
I've created a menu item with type com_finder and added the created search filter.
The result can be seen on our website.
Using the filter I've searched for _bootstrap_ in type = easydiscuss
As you can see in the dropdown "zoek op type" both types Articles and Categories are translated into our language Dutch.
This is because these items in de dropdown are language strings.
Both EasyDiscuss and Event (RSEvents) are not a language string and therefor not able to be translated.
You will make me very happy if the item can be translated.