WikiWaka is an app to to search and display articles from Wikipedia.
To easily navigate through longer texts you can use the "Table of Contents" which is provided for every article displayed.
Use the "Links" menu to look up more information related to the current article.
By default WikiWaka does it's search in the language you have set on your device.
You can switch to a different language inside the app, if you wish. That is only useful as long your keyboard supports the input of Roman letters.