Now Duolingo teaches the world's five most common languages

You can learn to speak a form of Arabic.

Duolingo's expanding language repertoire might just help you with a trip to the Middle East. The service now offers a course that teaches Arabic to English speakers -- specifically, a conversational version of the relatively universal Modern Standard Arabic. The program gradually introduces the alphabet, grammar differences and phonetics of the language to ensure that you're comfortable with the relatively difficult-to-learn linguistic structure.

The courses are available on Android, iOS and the web.

Whether or not you need to know Arabic, this marks an important milestone for Duolingo -- it now teaches the five most commonly spoken languages on the planet. You can generally assume that Duolingo will help you settle in a new country or make your next vacation slightly less intimidating. The service still isn't as flexible for non-English speakers (Arabic speakers can only learn a handful of languages). This is, however, a step in the right direction.