Engineered for rapid, effortless fluency
Oslango combines sensory immersion, cognitive spaced repetition, dynamic grammar mapping, and AI co-pilots into one seamless platform.
Multi-Sensory Practice Engine
Language is not just reading words on a screen. Oslango trains all 6 neurological pathways simultaneously.
Flashcard (FSRS)
State-of-the-art Free Spaced Repetition System (FSRS-5) operating per atomic definition (sense). Adapts interval spacing based on exact retrieval difficulty so you retain vocabulary permanently with 70% fewer reviews.

Grammar Mind Map & Dynamic Hierarchy
Grammar is not an isolated set of dry rules. Oslango visualizes grammar as an interconnected living graph with automatic difficulty levels.
Dynamic Level Engine
Node levels calculate automatically via level = max(child_levels) + 1. Leaf concepts start at Level 1, while mastery flows upstream seamlessly.
CEFR Breakdown & Limits
Topic details display visual CEFR distribution stacked meters (A1–C2). Start practice sessions with flexible question limits (10, 20, 50, 100 or custom counts).
BFS Cycle Prevention
Connect multiple prerequisites safely. Built-in 2-way Breadth-First Search (BFS) graph verification ensures 100% acyclic integrity without infinite study loops.
Interactive Live Streams & Immersion
Immerse yourself in authentic live streaming video, podcasts, and curated native broadcasts with synchronized transcripts and 1-click context capturing.
Real-Time Subtitles
Interactive dual-language transcripts synchronized to milliseconds. Hover any word for instant IPA, definition, and grammatical role.
1-Click Vault Capture
Instantly save unfamiliar terms, idioms, or entire spoken sentences directly into your personal learning Vault with original video timestamps.
Context Preservation
Words are never learned in isolation. Captured items retain the exact surrounding dialogue, tone, and source context for authentic recall.
Wall-Clock Study Timer & CEFR Pacing
Reaching fluency requires cumulative hours. Oslango tracks your exact engaged time and projects your target milestone arrival using rolling averages.
Zero-Loss Wall-Clock Tracking
Survives tab switches, page reloads, and mobile pauses
Active study timers compute duration dynamically via wall-clock time (Date.now() - createdAt - pausedMs). Sessions persist seamlessly in Cloudflare D1 with automatic 24-hour safety caps.
Rolling 7-Day Average Target Projection
Your estimated milestone arrival date adapts daily based on your real rolling 7-day study average (excluding today), giving you an honest, mathematical roadmap to fluency.
3-Way Retention & Habit Analytics
Raw test accuracy is misleading. Oslango calculates actual memory retention based on visual recognition, pronunciation precision, and spelling accuracy.
Sense Retention = (Remember + Pronunciation + Spelling) / 3
AI Daily Scheduler with ChatGPT & Claude
Connect Oslango's memory states directly to frontier AI models (ChatGPT, Claude, Cursor) to build personalized study routines tailored to your weak points.
Custom Study Parameters
Act as my elite language learning coach using Oslango's learning methodology.
Target Exam: IELTS
Current Goal: Transition from B2 to C1
Daily Study Budget: 45 minutes/day
Please create an optimized 7-day study schedule integrating:
1. FSRS Flashcard reviews (Target retention: 90%)
2. Pronunciation & Shadowing practice (16 mins/day)
3. Grammar Mind Map mastery on complex sentence structures
4. Authentic Dictation & Stream immersion
Format the output as actionable daily checklists with exact Oslango practice modes and estimated completion times.
Paste this structured prompt into ChatGPT, Claude, or your Cursor agent to generate custom weekly milestone checklists synced to your Oslango memory curves.