COCA 16515: Q.Z.L Corp.’s Vocabulary Master for the Gemini 3 Hackathon

COCA 16515: Our Hackathon MVP for the Gemini 3 Hackathon

We’re excited to announce that Q.Z.L Corp. is joining the Gemini 3 Hackathon with our project COCA 16515!
You can also see our preview on Devpost here: https://devpost.com/software/coca-16515.

What is COCA 16515?

COCA 16515 is a web and mobile-based vocabulary learning platform built around the 16,515 most frequent English words from the Corpus of Contemporary American English (COCA).
It provides bilingual definitions (English–Chinese), context-rich examples, multiple usages, and pronunciation guides, helping learners study more effectively and track their progress toward mastery.

Demo Video

Watch COCA 16515 in action:

Inspiration

The project was inspired by my own experience preparing for IELTS, required for my Canadian Permanent Resident application. Memorizing random word lists didn’t work, but studying frequency-based, context-rich vocabulary made a huge difference. I wanted to create a tool that could help others learn smarter, track progress, and truly master English words that matter.

What it does

Offers 16,515 COCA words with bilingual definitions and examples.

Tracks user XP, streaks, and mastery goals.

Provides flashcards, quizzes, and a word browser for interactive learning.

Allows learners to study daily, revisit difficult words, and monitor progress.

Try it live here: Web App
Android app with ads: Google Play
Android app paid, no ads: Google Play Paid

How we built it

Next.js for a fast, responsive web frontend.

TailwindCSS for a clean, modern interface.

TypeScript for maintainable and scalable code.

COCA 16,515 dataset for detailed definitions, examples, and pronunciations.

Dynamic learning flow to prioritize user engagement and context-based mastery.

Challenges We Ran Into

Structuring a large vocabulary dataset for interactive learning.

Designing a dashboard that motivates learners without overwhelming them.

Handling bilingual content while keeping the interface clean.

Maintaining engagement across thousands of words.

Accomplishments

Successfully integrated all 16,515 COCA words with definitions, examples, usage, and pronunciation.

Built a bilingual, context-rich learning interface.

Created a progress tracking system with XP, streaks, and mastery goals.

Turned personal IELTS preparation experience into a scalable learning tool for others.

What We Learned

Frequency-based vocabulary like COCA is far more effective than random lists.

Context and examples improve retention and understanding.

User motivation and habit design are as important as content itself.

Large-scale learning apps require balancing data complexity and interface simplicity.

Next Steps for COCA 16515

Add adaptive learning algorithms to prioritize challenging words.

Implement spaced repetition and smart quizzes for faster mastery.

Expand bilingual support beyond Chinese–English.

Build mobile support improvements for on-the-go learning.

We can’t wait for everyone to try COCA 16515 and experience how context-rich, frequency-based learning can accelerate English mastery!

Try it now: Web App | Android with ads | Android paid, no ads