I was very happy to find an app that uses the phonetic system that is used in Taiwan, however, it is not very useful unless you already know them. This app simply allows you to pair the phonetics that can go together and then pronounce them for you with the tone that you have chosen. That is helpful when learning which phonetics go w/ which and then how they are pronounced, but this app does not teach you the order they go in or how the individual phonetic is pronounced by itself, unless it is a word by itself: like in English, it word pronounce 'a' for you, because that, by itself is a word, but it wouldn't tell what the letter s was unless you paired it w/ another letter, to make 'is' for example.
There are also no directions on how to use it, although it is pretty simple once you figure it out. I would like to see an app that has way more features than this one does, but for a free app, if you just need to know how to pair up the phonetics and how they are pronounced, this app is good enough for that.