Bilingual offline-first learning app for Vietnamese and German.

A language-learning app that runs entirely offline on the device: a path of levels that build on each other, spaced repetition via FSRS and 17 exercise types, from plain flashcards through cloze and listening drills to crosswords and free writing. The curriculum is written by a Python pipeline: it builds a difficulty ladder from freely licensed sentence corpora using word frequency, derives the exercises deterministically from each card id, and has a language model add the grammar lessons, the word-by-word breakdowns and the illustrations, plus TTS audio. Both directions come out of the same sentence pairs, German to Vietnamese and back, each with a matching interface language.