WordRoll language apps
WordRoll translator apps for iPhoneTranslator app reviews
World Nomads (free)
24/7 tutor (free)
Cool Gorilla (99¢)
Word Roll (99¢)
Lonely Planet ($9.99)
Usability: WordRoll apps are just dictionaries, not phrase books (and have no audio function to help pronunciation).
However, each comes fully loaded with tens of thousands of words in your choice of seven language (each app is sold separately).
Within each app, you can easily switch between languages (look up the German based on the English or vice versa), and—for a dollar app—it has an impressive number of entries, between 24,000 and 35,000, depending on the language.
Frustrations: Many words have multiple synonyms or different meanings, and to its credit WordRoll presents all possible definitions/translations. However, they're merely listed, in alphabetical order, without further explanation. You don’t know which of the seven Italian offerings for "have" means accept, possess, have, host, take, procure, or receive—or that the Italian word for the kind of bed that you sleep on is the fourth one down on the list (after the Italian word for the kind of bed in which you plant flowers and just before the Italian for "layer").
That said, it's most useful for translating words from the local lingo into English, since at least you'll have context to figure out the correct definition.