Codex4 - Language Learning
Learn a new Language
Only for iPhone
Free · In‑App Purchases · Designed for iPhone
iPhone
Get fluent faster by learning the words you actually use.
Codex4 helps you build a usable vocabulary and keep it for the long term.
- Learn what you need: Add your own words from any text in one tap. Build vocabulary for your job, studies, or hobbies.
- Retain more with less effort: Reviews are timed by FSRS (a modern spaced-repetition model) so you study exactly when it counts.
- Master real usage: The app treats each word as a lemma, so forms and conjugations are covered naturally as you progress.
- Stay organized and motivated: Clear stats show what’s due, what’s known, and what’s next.
- Bring any content: Automatic word extraction and a context-aware lemmatizer handle homonyms and multi-word phrases.
- Your data stays yours: Keep access to review even after unsubscribing, and export your words and learning data anytime.
- No gimmicks: Fast sessions, clean design, built for serious learners.
Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Ratings & Reviews
Improved the experience for new users.
The developer, Jonas Richner, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Linked to You
The following data may be collected and linked to your identity:
- Usage Data
Data Not Linked to You
The following data may be collected but it is not linked to your identity:
- Contact Info
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Jonas Richner
- Size
- 35.5 MB
- Category
- Education
- Compatibility
Requires iOS 15.6 or later.
- iPhone
Requires iOS 15.6 or later. - iPod touch
Requires iOS 15.6 or later. - Mac
Requires macOS 12.5 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- Languages
- English
- Age Rating
4+
- 4+
- In-App Purchases
Yes
- Basic $12.99
- Basic Yearly $85.00
- Pro Yearly $200.00
- Pro $29.99
- Copyright
- © 2025 Jonas Richner Software