What guarantees the success? Vocabulary Trainer has a database with the most important words and phrases used in the spoken language.
So the most important features:
✓ Database with most important words and phrases of the spoken languages.
✓ Speech engine able to speak both languages used in the app.
✓ Training your weak areas: while doing simple training, Vocabulary Trainer analyses your results and you can do training which focuses on areas your are weak on.
✓ Statistics to see how are you becoming better and better.