Duolingo is THE app for learning a new language but one of the heaviest hitters in the Language Learning world can also be accessed through an app. Rosetta Stone is available on mobile devices to help you reach your more than monolingual dreams.
Rosetta Stone has been around for quite some time and uses an immersion teaching style to help people pick up 21 popular languages. Rosetta Stone proper is also really, really expensive but it is generally well rated. The free app allows you to sort of test out the system before dropping a bunch of cash on it.
If you’ve already paid for Rosetta Stone, you can get access to the full mobile package but this app lets you test out lesson one first so you can at least figure out if it works for you before committing to the full price of the service. It does have a few languages that Duolingo does not so depending on your goals, it may be a better option for you. The Rosetta Stone app is free for the first lesson.