There's only one way to really master a foreign language: practice. The more you practice, learn, and speak, the better you get and it's crucial that you keep it up on a regular basis. This is why a good mobile app might be the best learning tool for foreign languages yet invented outside of living in a foreign country. To make the most out of it though, you need an app that a) actually works and b) is appealing enough to make you want to use it.
We've all been fooled by a flashlight or mirror app that just doesn't work so I don't have to tell you that there are a lot of crummy apps out there. Surprisingly, plenty of them actually make it onto lists that claim to be the "best apps for X."
With that in mind, I did some research to track down 5 apps that:
Actually work
Are cheap
Are fun and engaging.
Next, as a lapsed French speaker, I road tested them myself. Most of them will be useful for learners at a variety of levels, from beginner to advanced/intermediate. So if you're studying for the December SAT Subject Test in a foreign language, take heed and get your study on with these apps!