Currently I am working on a part of a wikimirror project that involves doing a search in wikipedia and retrieving snippet of text with searched terms being highlighted. I would like to improve what I am doing at the moment by highlighting also different forms of a given word. For example if user types in: 'playing' I would also highlight play, plays, played and so on. In wikipedia this already works like this: https://en.wikipedia.org/w/index.php?title=Special%3ASearch&profile=defa... I would like to ask what technics (plugins, libraries, extensions) wikipedia uses to do this type of highlighting. I would appreciate any answer.