Hello vp101-Team,
first of all I want to say that I like to learn Vietnamese with vp101, it makes fun and I think that I make more progress compared to other courses that I have tried before. I have learned that the pronounciation is of vital importance, and try to perfect my pronounciation using your vocabulary and examples. The differences of accents are sometimes not easy to gasp! Here I need to rely that the speaker says the word exactly with the correct pronounciation. Unfortunately this is not always the case, and today I happened to stumble upon some of such negative examples... To name a few, look at "indigo" and "red" from "Core 2000 Word List". So if possible, do review once the word lists and vocabulary, I know it is a huge work, but we students need it! Maybe it would help to add to every example, flashcard or vocabulary word a small button something like "report a mistake" so the students can click it if in doubt and you could put your attention to review it.
Mihail