Master Pronunciation
from Day One.
Capture Real Lessons. Clean the Audio. Retain for Life.
Coursi is the offline sound-to-image language companion built for live classrooms, tutoring sessions, and immersive study. Record authentic teacher pronunciations, strip away background classroom noise with built-in studio DSP, attach whiteboard notes, and practice with interactive A/B voice comparison—all on your terms, 100% privately on your device.
No account required • Zero server uploads • Full DSP engine included
Synthetic voices don’t prepare you for real human conversations.
Most language apps rely on synthetic, robotic text-to-speech (TTS) engines and disconnected multiple-choice drills that fail in real-world conversations. Meanwhile, serious language learners sitting in classrooms or working 1-on-1 with native tutors struggle to capture fleeting pronunciation nuances, tone contours, and whiteboard diagrams in real time.
Coursi bridges the gap between live instruction and long-term retention. Rooted in the sound-to-image vocabulary acquisition philosophy, Coursi lets you tap to record your teacher in seconds without interrupting class, automatically cleans up AC hum and desk rustle with built-in audio engineering filters, pairs the audio with a photo of the whiteboard or textbook, and turns every lesson into an interactive, spaced-repetition flashcard deck.
Engineered for the Modern Classroom
In-Class Lesson Recorder & Whiteboard Capture
Never scramble during fast-paced lectures. Hit record in one tap without typing text. Capture the teacher’s phrase, snap the chalkboard diagram, and label your entry later.
- Zero-friction in-session recording with optional text input
- Multimodal cards: Native audio, IPA/phonetics, translations & whiteboard photos
- Live RMS decibel monitoring to verify clean teacher pickup from any seat
On-Device Audio Cleanup & Precision Waveforms
Classrooms and cafes are full of AC hum and desk rustle. Coursi features an on-device digital signal processing engine that cleans raw 16-bit PCM WAV audio right on your phone.
- Classroom Denoise: 85 Hz Butterworth high-pass filter cuts AC and rumble
- Smooth-envelope noise gate attenuates background room chatter between words
- Dynamic gain & peak normalization to -1 dB with soft tanh saturation protection
- Visual multi-bar amplitude visualizer to crop dead air down to the millisecond
Sound-to-Image Flashcards & A/B Voice Comparison
Turn live lessons into interactive spaced-repetition drills. Record your voice next to your tutor’s, analyze waveform peaks side-by-side, and loop tricky liaisons.
- Interactive A/B student voice comparison with visual waveform matching
- Variable pitch-preserved playback speeds: 0.5x, 0.75x, 1.0x, and 1.25x
- Continuous loop mode to drill muscle memory and native cadence
- 3D animated flip cards combining audio, whiteboard notes, and translations
Multi-Language Isolation Shell
Studying multiple languages simultaneously? Coursi keeps each language in a strict sandbox so vocabulary, decks, and audio files never collide.
- Isolated per-language workspaces for total focus
- Custom regional flags and academic icon markers
- Organize entries by textbook chapter, tutor session, or conversation topic
100% Offline Privacy & Portable .coursi Archives
Your voice recordings and classroom notes never touch third-party cloud servers or AI training pipelines. Back up your library into an open, single-file container.
- Zero mandatory cloud accounts, zero tracking telemetry, 100% offline functionality
- Single-file .coursi (ZIP) export containing uncompressed WAVs and full-res photos
- Seamless backup and restore via iCloud Files, Google Drive, AirDrop, or USB
On-Device Studio DSP (Audio Cleanup & Editing)
Real classrooms are noisy. Coursi features a custom on-device Digital Signal Processing pipeline that cleans raw 16-bit PCM audio locally with zero latency:
Classroom Denoise
Eliminates low-frequency air conditioning rumble, desk bumps, and paper rustle with a 2nd-order Butterworth high-pass filter.
Smooth Noise Gate
Intelligently attenuates background murmur and ambient classroom chatter during natural pauses between spoken words.
Dynamic Gain & Ceiling
Balances quiet teachers and distant voices to an optimal, distortion-free −1 dB ceiling with soft tanh saturation protection.
Precision Waveform Trimmer
Visual multi-bar amplitude waveforms let you crop dead air before and after phrases down to the millisecond with 1-tap presets.
Who is Coursi Built For?
Classroom & University Students
Teachers speak quickly; whiteboard notes get erased before audio context can be written down.
Tap-to-record voice clips, take whiteboard photos, and organize by date and lesson unit instantly.
1-on-1 Tutoring & Immersion
Synthetic TTS apps cannot teach local slang, regional accents, or nuanced conversational cadence.
Record native tutors directly, boost quiet speech, and review with authentic human inflection.
Phonetics & Pronunciation Enthusiasts
Hard to detect where your own accent deviates from a native speaker.
Visual waveform peak matching, continuous looping, 0.5x slow-motion, and side-by-side A/B voice drills.
Polyglots & Multilingual Learners
Flashcard apps frequently merge or confuse vocabularies across different language tracks.
Strict Language Shell architecture isolates audio, decks, and metadata for every language you speak.
Privacy-Focused Learners
Cloud-based apps harvest audio data and require persistent online connectivity.
100% local on-device operation, zero server telemetry, and user-owned .coursi offline backup archives.
Permanent Tools, Not Recurring Rent.
We believe language acquisition tools should be permanent study assets, not unending monthly subscriptions.
Free Evaluation
Test the complete workflow in your next tutoring session.
- Up to 20 recorded phrases across all lessons
- Full DSP audio cleanup studio
- High-resolution photo whiteboard attachments
- Sound-to-image flashcard reviews
- .coursi backup & restore
- Completely Ad-Free, no sign-up required
Coursi Pro
Pay once, own forever. Family sharing supported.
- UNLIMITED phrases & recordings
- UNLIMITED lesson decks across all languages
- Multi-language isolation shell
- Full on-device DSP audio editor & presets
- Interactive A/B voice comparison lab
- Lifetime updates • Zero recurring subscriptions forever
Technical Specifications
Architecture & Audio Engineering Specs
Take Control of Your Pronunciation Today.
Download Coursi on iOS and Android. Start with the free evaluation—no credit card or registration needed.