iTranslate Converse
With a dead-simple interface and near real-time operation, iTranslate Converse is a must-have for your next trip abroad. Once you select the two languages it needs to listen for, flip your phone upside down (the better to pick up both people's voices) and press down on the screen while you talk. It will automatically determine which language is being spoken and translate it to the other, speaking the translation aloud. It also saves text transcripts of your chats, and should you spring for the Pro version, you'll get unlimited translations per month — limited to 300 in the free version — as well as audio transcripts. Currently exclusive to iOS with support for 38 languages.