Create a flash card generator aimed at people studying a new language which will identify words and phrases for the user to study based on frequency and the user's past performance with the word.

Simply put - I am aiming to create a flash card system which finds your weaknesses, targets them, and uses them to extrapolate where else in the language you may be weak.

My own experience learning French is my motivation for this. One metric to improve one's ability with a new language is to simply accumulate words and phrases. However, this has some weaknesses:

1. You have to identify them, and set them aside.
2. Our perception of our own ability with flashcards can be biased.
3. You have no metric giving how useful the word actually is.
4. Often, flashcards can be shallow. Often, we may simply look at a word, and translate. Ideally, we should be learning it in context.

I seek to improve upon the system by providing a program which allows the user to define the set of words that they want to study using text which is relevant to some topic. For instance, as an intermediate level learner with a career in finance, I may want to emphasize words commonly used in business. It doesn't make sense for me to create a generic deck of French flash cards, I should take one of the economics articles from Le Figaro.