HSKinter
Chinese Words Study (HSK 1–5) on Desktop and Phone
A Python/Tkinter tool to learn 2500 Mandarin words (HSK 1–5).
Flashcards, practice of hanzi meaning, pinyin and tones, stats of accuracy. Optional pronunciation via gTTS (Google). Compatible with Pydroid 3 (runs on Android).
The frequency of a word showing up depends on its retaining level and time since the last answer (age).