final_levels:
- general
- vocab
- tense
- clause
TODO
- deal with cases where there's no available transcript or translation
- rank videos based on matching score
- levelling up when video is watched x times
- or by taking average of vocab words?
- fix the default values of Video attributes
- language acquisition theory - 5 hypotheses
- how does our app put this in practice? how did we figure out the grammar/theory part so the user doesn't have to?
- the apis we used
- youtube
- transcript
- cathoven
- how we're incrementing the difficulty using analysis from cathoven