Features
Everything in duiduidui! serves one goal: actually learning Chinese. The features fall into three groups: an engine that models you, a map of the whole language, and the companions (human and AI) who learn alongside you.
The Engine: Study That Models You
An adaptive flashcard system built on a real mathematical model of your knowledge. It calibrates to your level with no placement test, keeps you challenged without burying you, and reports progress you can trust. The full details are on Why It Works and, for the brave, the mathematics page.
The Dictionary: A Map of the Whole Language
Not a word list: a knowledge graph of 200,000+ interconnected entries built from the ground up for learning. Every character, word, phrase, and sentence is linked to its components, tagged by concept, and scored by difficulty. And the whole thing lives on your device.
Characters
5,100 characters with difficulty rankings individually curated against our scoring rubric, plus 1,100+ alternate-sense entries for homonym disambiguation
Words & Phrases
51,000+ words and 30,000+ phrases showing how characters combine
Sample Sentences
116,000+ sentences demonstrating real-world usage in context
Radicals
Character components that reveal the patterns inside Chinese
Difficulty Scores
Every entry ranked on a progressive difficulty scale
Tags & Taxonomy
Concept categories and custom tags for organizing your learning
Always Offline
Dictionary lookups, flashcard reviews, and search, all without Wi-Fi
Smart Search
Search by Chinese, pinyin, or English, with filters for tags, difficulty, and mastery
Natural Speech
Natural-sounding pronunciation for every record in the dictionary
Personal Phrasebook
Star any entry to save it, then run focused study sessions on your selections
The Companions: Never Study Alone
An AI tutor that knows the dictionary and your progress, an open MCP server so your own assistant can join in, and progress sharing for the humans who guide you. Working with a tutor? See duiduidui! for Teachers.
问老虎 · Ask the Tiger
Chat with 老虎 (lǎohǔ, "tiger"), the built-in tutor: ask about the language or your own learning, and let it look things up and act on your behalf
Connect Your Own AI
Plug Claude, ChatGPT, or Gemini into your account through our public MCP server, with the same tools the in-app agent uses
Teachers & Students
Share granular progress with your teacher, who can follow along through study logs, the built-in agent, or their own AI
Friends & Family
Study together, track each other's progress, and keep each other motivated
Built with AI
Agents inside the app and behind it: the dictionary, the curriculum scoring, and much of the code, all under human direction