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The Complete Guide

How FlexiLingo Works:One Extension. YouTube, BBC & CBC.

FlexiLingo is an AI-powered browser extension that turns videos and podcasts into interactive English lessons. CEFR-leveled vocabulary, 5 active learning modes, AI transcription, NLP analysis, and spaced repetition—all inside your browser, on the platforms you already use.

Install Free Extension Create Free Account

YouTube, BBC & CBC supported

CEFR levels A1–C2

4 learning modes + Quiz

Spaced repetition (3 algorithms)

AI-powered transcription

NLP content analysis

Try the Built-in Podcast Player

No extension needed — play a real podcast episode, follow along with AI subtitles, and click any word to see its translation.

Try it yourself

#371 Dogs and their superpower

Speak English Now Podcast: Learn English | Speak English without grammar.

0:00

Click any highlighted word to see its meaning

Try the Built-in Podcast Player

No extension needed — play a real podcast episode, follow along with AI subtitles, and click any word to see its translation.

Try it yourself

In This Guide

Getting Started

From Install to First Lesson in 5 Minutes

FlexiLingo works as a Chrome extension. Install it once, and it activates automatically on supported platforms.

Install the Extension

Add FlexiLingo to Chrome from the Chrome Web Store. It's free and takes seconds.

Open a Video or Podcast

Go to YouTube, BBC, CBC, or Spotify. Play any content that interests you.

Launch FlexiLingo Studio

Click the FlexiLingo button on the player or press Alt+S. The Studio panel opens with interactive subtitles.

Click, Save & Learn

Click any word to see its CEFR level, definition, and example. Save it to your deck with one click.

Review with Flashcards

Open your dashboard to review saved words with spaced repetition. The system schedules reviews automatically.

Install FlexiLingo — Free

Supported Platforms

One Extension, Multiple Platforms

FlexiLingo works wherever you watch or listen to English content. No switching between apps—one tool for all your learning.

YouTube

Full support for every YouTube video. Native captions, AI transcription when subtitles are missing, karaoke-style word highlighting, and all learning modes.

Native closed captions + AI transcription backup

Karaoke mode with active word highlighting

Works on any video: TED Talks, vlogs, news, courses

BBC (News, Sounds, iPlayer)

Learn from BBC News articles, BBC Sounds podcasts, and BBC iPlayer content. Perfect for British English and IELTS preparation.

British English with diverse regional accents

AI transcription for content without subtitles

News, documentaries, podcasts, and educational content

CBC (Radio, News)

Canadian English from CBC Radio and CBC News. Essential for CELPIP preparation and understanding Canadian accent and vocabulary.

Canadian English for CELPIP preparation

Radio programs with real-time transcription

News coverage with Canadian vocabulary and topics

Spotify Podcasts

Learn from thousands of English podcasts on Spotify. FlexiLingo captures transcripts and applies interactive subtitles.

Podcast transcripts with interactive subtitles

Wide variety: news, education, entertainment, interviews

Synced lyrics for music tracks

See all supported platforms

Vocabulary Intelligence

Every Word Color-Coded by Difficulty (CEFR A1–C2)

FlexiLingo assigns a CEFR difficulty level to every word in the subtitle. At a glance, you know exactly which words are beginner-friendly and which are advanced.

Words are color-coded with a subtle bottom border. Beginner words (A1–A2) appear in green, intermediate (B1–B2) in yellow/orange, and advanced (C1–C2) in red/purple. This means you can focus on words at your current level or challenge yourself with higher-level vocabulary.

Example: In the sentence "The unprecedented surge overwhelmed the infrastructure," the words "the" (A1) and "surge" (B2) and "unprecedented" (C1) and "infrastructure" (C1) each get different colors—so you instantly see the difficulty landscape of every sentence.

A1 — Beginner: Basic everyday words (hello, house, eat, go)

A2 — Elementary: Simple phrases and routine tasks (appointment, direction, schedule)

B1 — Intermediate: Handle most travel and work situations (advantage, consumer, perspective)

B2 — Upper Intermediate: Complex topics and abstract ideas (infrastructure, sustainable, controversy)

C1 — Advanced: Nuanced expression and academic language (unprecedented, intricate, encompass)

C2 — Proficiency: Near-native mastery (juxtaposition, ephemeral, ubiquitous)

Active Learning

4 Learning Modes + Quiz — From Passive Watching to Active Mastery

FlexiLingo offers four active learning modes inside the extension while watching videos. Switch between modes anytime. Plus, a dedicated Quiz system on the dashboard for focused practice.

Extension

Learn Mode

Full access to translations, CEFR colors, and word details. Click any word for its definition, pronunciation, and example sentences. Perfect for exploration and discovery.

Extension

Challenge Mode

Translations are hidden until you tap. Test yourself first, then reveal the meaning. Great for checking how much you actually understand without support.

Extension

Cloze Mode (Fill-in-the-Blank)

Random words are blanked out from the subtitles. Type the missing words as the video plays. Adjustable difficulty: hide 20% to 80% of words.

Extension

Dictation Mode

Listen to the audio and type what you hear—no subtitles shown. Perfect for improving listening comprehension and spelling. Character-level feedback shows exactly where you went wrong.

Dashboard

Quiz (Dashboard)

Take focused quizzes on the FlexiLingo dashboard based on your watched content. Multiple choice, fill-in-the-blank, word reordering, and more. Choose General, IELTS, or CELPIP mode.

Analysis Results Preview

Grammar Counts: 12× past perfect, 8× conditionals, 5× passive voice

Phrasal Verbs: come up with, break down, look into, carry out

Collocations: make a decision, take advantage, draw attention

CEFR Distribution: 40% B1, 30% B2, 15% C1, 15% A2

Overall Difficulty: B2 (Upper Intermediate)

NLP Analysis

AI-Powered Content Analysis: Understand Every Layer

FlexiLingo doesn't just show subtitles—it analyzes the entire content with Natural Language Processing. Get counts of grammar patterns, detect collocations, identify phrasal verbs, and see a full difficulty breakdown across the whole content.

Grammar Pattern Counts — shows how many times each grammar pattern (past perfect, conditionals, passive voice, etc.) appears across the entire content

Phrase & Idiom Detection — automatically finds collocations, phrasal verbs, and idiomatic expressions worth learning

CEFR Distribution Chart — see the percentage breakdown of vocabulary difficulty across the entire content

Vocabulary List by Level — organized word lists sorted by CEFR level with definitions and context sentences

Overall Difficulty Score — a single number (0–100) telling you how challenging this content is for your level

AI Transcription

No Subtitles? FlexiLingo Creates Them with AI

Many videos and podcasts don't have subtitles. FlexiLingo uses OpenAI Whisper to generate accurate transcriptions automatically—so you never miss a word.

Whisper AI Engine

Real-Time Progress

Watch transcription happen in real time. Segments appear as they're processed—no waiting for the full transcript.

Works on Audio-Only Platforms

BBC Radio, CBC Radio, Spotify podcasts, and other audio-only content gets full subtitle support through AI transcription.

Automatic NLP Enhancement

Once transcribed, subtitles are automatically enriched with CEFR levels, translations, and word status—just like native captions.

Vocabulary Building

Click a Word. Save It. Never Forget It.

Building vocabulary is at the heart of FlexiLingo. Click any word in the subtitles to see its full profile—definition, CEFR level, pronunciation, example sentence, and part of speech. Then save it to your personal deck with one click.

One-Click Save

Click any word → see its definition and level → tap 'Save' → it's in your deck. No copy-pasting, no switching apps.

Context Preserved

When you save a word, FlexiLingo remembers the original sentence, the video timestamp, and the topic. Context makes words stick.

CEFR Level Attached

Every saved word carries its CEFR level, so you can filter your deck by difficulty and focus on your target range.

Bulk Add from Analysis

After AI analysis, you can bulk-add entire word lists (all B2 words, all phrasal verbs, etc.) to your deck in one action.

My English Deck

unprecedentedC1

sustainableB2

infrastructureC1

Learn more about vocabulary collections

Never Forget

Spaced Repetition: Remember Words Forever

FlexiLingo includes a built-in spaced repetition system (SRS) with three proven algorithms. The system automatically schedules your reviews at the optimal time for long-term memory retention.

Leitner System

The classic 5-box system. Words move to higher boxes as you learn them. Simple, visual, and proven effective.

SM-2 Algorithm

The SuperMemo 2 algorithm. Adjusts intervals based on how easily you recall each word. More adaptive than Leitner.

FSRS Algorithm

The latest Free Spaced Repetition Scheduler. State-of-the-art algorithm with the best memory retention rates.

Choose your preferred algorithm in Settings. All three track your progress across devices. Start with Leitner if you're new to SRS, or try FSRS for the most optimized experience.

Your Learning Hub

Dashboard: Track Everything in One Place

The FlexiLingo web app is your learning headquarters. Review flashcards, track progress, manage decks, explore podcasts, and see your growth over time.

Analytics & Insights

Visual charts showing your daily activity, accuracy trends, streak history, and vocabulary growth over time.

Deck Management

Create, organize, and share vocabulary decks. Import/export cards, set visibility (public/private), and explore community decks.

My Analyses

All your analyzed videos and texts in one place. Filter by CEFR level, sort by date or word count, and revisit any analysis.

Daily Goals

Set daily targets for words reviewed and study time. Track your streak and stay consistent with visual progress indicators.

XP & Achievements

Earn experience points for every activity—words reviewed, quizzes completed, streaks maintained. Unlock achievements as you progress.

Podcast Discovery

Browse curated English podcasts filtered by CEFR level and topic. Request new podcasts and track your listening progress.

Create Your Free Account

Exam Preparation

Prepare for IELTS, CELPIP & TOEFL with Real Content

FlexiLingo isn't a practice test generator—it's a tool that turns real English content into exam preparation material. Listen to authentic accents, build academic vocabulary, and train your ear for the actual exam.

IELTS Preparation

Use BBC content for British English listening. Build academic vocabulary from TED Talks and documentaries on YouTube. Practice with diverse accents—exactly what IELTS tests.

CELPIP Preparation

CBC Radio and CBC News provide authentic Canadian English—the accent and vocabulary CELPIP focuses on. Build listening skills with real Canadian content.

TOEFL Preparation

Academic YouTube channels, university lectures, and educational content provide the academic English TOEFL requires. Save and review key vocabulary systematically.

Read: IELTS 30-Min Daily Plan Read: CELPIP Preparation Guide

Studio Layouts

Studio Layout: Fullscreen Mode + More Coming

FlexiLingo's Studio currently runs in Fullscreen Mode—an immersive learning environment with all tools at your fingertips. More layout options are on the roadmap.

Fullscreen Mode

Available Now

Maximized studio with the video in the background. All tools at your fingertips—subtitles, analysis, vocabulary, learning modes. Best for focused, deep learning sessions.

Split Mode (Left/Right)

Coming Soon

Video on one side, Studio on the other—50/50 split. Watch and study simultaneously without overlapping. Great for desktop.

Cinema Mode

Coming Soon

Subtle side panel that minimizes distraction. The video stays front and center while learning tools stay accessible on the edge.

Overlay Mode

Coming Soon

A floating translucent panel over the video. Movable and resizable. Minimal footprint for casual learning while watching.

Picture-in-Picture (PiP)

Coming Soon

Video shrinks to a small floating window. The Studio takes the main screen. Full study features with the video always visible.

Audio Learning

Learn English from Podcasts — Not Just Videos

FlexiLingo isn't limited to video content. It works with podcasts on Spotify, BBC Sounds, and CBC Radio—generating transcripts, adding CEFR levels, and giving you the same interactive learning experience.

AI transcription for audio-only content (BBC Radio, CBC Radio, Spotify podcasts)

Curated podcast library with CEFR-rated episodes on the FlexiLingo dashboard

Browse by topic (business, science, culture, news) and accent (British, American, Canadian, Australian)

Request new podcasts—the community helps expand the library

Read: Spotify Podcasts + FlexiLingo Guide