LangVault
A Mandarin study app that builds spaced-repetition review and constrained conversation practice from a learner's own vocabulary.
Overview
I built LangVault to make Mandarin practice follow the vocabulary a learner has actually studied. Instead of presenting a fixed curriculum of unfamiliar material, the iPhone app centers study on a personal Word Bank and Phrase Bank.
Approach
The learner’s saved words and phrases become the source for generated flashcards and spaced-repetition review. For active practice, a large language model generates sentence-building and conversational exercises on demand, then provides tailored feedback. The exercise design constrains generation to the learner’s existing material so practice remains usable at their current level.
The Word Bank keeps Mandarin characters, pinyin, English meanings, and pronunciation audio together. Conversation Builder turns that study material into writing practice, comparing a learner’s response with an expected response and offering a suggested correction.
Results
In my own Mandarin study, spaced-repetition review has helped me revisit vocabulary consistently, while the constrained exercises have given me much more active sentence-building practice with words I already know. I have found that combining the two has noticeably accelerated my learning.
The Progress view summarizes daily flashcard ratings and their distribution over time, making it easy to revisit review history alongside ongoing practice.
