If there's one thing the internet hasn't managed to get absolutely perfect yet, it has got to be language translation. Language can be so nuanced and it's hard for a computer to get it right every time. Even Google Translate, with all of its resources, is known for its embarrassing blunders. While you'll never be able to count on 100% accuracy when it comes to translation apps, you can still get close enough if you find yourself in a spot of trouble.
Siri is actually a bit of a hidden resource when it comes to languages. The voice assistant can translate Chinese, German, Spanish, French, and Italian, and does a pretty good job of it, too. To make the most of this feature, simply ask "Siri, how do I say..." or "Siri, translate..." You'll get an audio translation, as well as a written one.