
Dict Thai is an English-to-Thai dictionary with several lookup methods: typed search, word-category listing, irregular verb tables, and bookmarked entries. Pronunciation of English words, romanization of Thai words, and lookup of more advanced irregular verb tables each require an in-app purchase of $0.99.
Dict Thai's intended audience is ambiguous. Despite having an interface and developer description entirely in English, the actual application seems more geared to looking up the Thai definitions of English words. The Thai language uses its own script, which makes it impossible for the English reader to determine how to even estimate a pronunciation of the word without the in-app romanization purchase or research elsewhere. Even with that addition, choosing the right translation when multiple are available is a tossup for those who can't read and understand the Thai definition.
It seems that the application would be most useful as an advanced reference to those who already know the basics of both languages.
Sam's Related Factoid: The Thai-speaking synthetic System Voice in Mac OS X is called Narisa.