I am a professor of literacy and I reviewed this app for possible use in adult basic literacy. The format of this is clean and appealing, which suits adult learning. I applaud that two examples of context are included. I could not figure out how to create a study set. Sound quality is excellent.
The problem, however, is that the limited word list is quite sophisticated for struggling learners. I would hope to find some choices in word lists in the future. Also, it is not logical to choose words for study based on parts of speech. People do not learn words that way. There is potential here, with some more development.