Haiku uses a layout manager to position the elements of the GUI, like text fields, buttons, boxes, pop-up menus etc. The layout manager allows for the GUI to change size dynamically depending on the length of words, which may changes with different languages, sometimes this can have strange effects.

For this task you'll have to go through all Haiku's applications, preference panels etc. and look for these anomalies.  Alternate the language selections and retry using multiple different languages and make note of any strange behaviors.

Keep a list of all the programs and languages you've tested (don't forget possible settings windows etc.). Report problems together with screenshots in our bug tracker.