The pronunciations are easy to understand and there seems to be a very large selection of words. Two suggestions I have for change are:
1. Change the icon. Its too complicated and busy. Very un-Apple-like.
2. Change the formatting for the word submission page. It is very difficult the read the word you want to submit for inclusion in a future update.
I also noticed that you cant replay a pronunciation. You have to go back to the list and then re-click on the word to hear the pronunciation again.
EG1400 about Microbiology Pronunciations