I've been trying a variety of free English-Thai translation aps for my android phone, and finally found one worth mentioning.

 

It's called QuickDic and is notable for 2 main reasons:

1. It downloads its dictionaries to your phone, so you don't need internet access to use it (unlike most aps)

2. It supports a wide variety of other languages

 

Although it is pretty limited, it has proven to be very useful in helping talk with the girls.

 

Worth a few minutes to test for yourself, and I'd be interested in any more experienced BM's feedback - especially if you've found a better translation ap.

https://play.google.com/store/apps/details?id=com.hughes.android.dictionary&hl=en