I just got back from Brazil and I realized how much travel has changed...and a large part of it is Google.
I had a SIM card for my phone, so thanks to Google Maps, I was able to navigate the streets of Sao Paolo (safely, I might add).
I was able to use Google voice to text home to the NFO.
But the app that changed the game for me was Google Translate. I had a full on conversation with my taxi driver simply by talking to him and having him talk back into the phone.
In a bar, I held my phone up using the camera function and via Translate, it superimposed the translation of the Portuguese sign into English in front of my very eyes.
It was crazy.
I was able to order drinks, communicate with shop workers, and more. No more hand signals or drawings.
Now, while I'm here, I do need to mention another app which I think is incredibly useful, because although Google is great, you need wi-fi or a data connection to make it work. Plus, it doesn't teach you the language, it just helps you survive.
On the other hand, if you want to learn a language AND have it available to you offline (can be VERY valuable) check out Smigin. It's very slick.