Step-by-Step Guide: Building a Duolingo Clone with Adalo

Building a language learning app like Duolingo seems like a massive undertaking—gamified lessons, streak tracking, progress systems, and cross-platform availability all require significant development resources. Traditional app development would demand separate codebases for iOS, Android, and web, plus months of coding and testing before you could even think about launching to app stores.

That's where Adalo comes in. Adalo is a no-code app builder for database-driven web apps and native iOS and Android apps—one version across all three platforms. AI-assisted building and streamlined publishing enable launch to the Apple App Store and Google Play in days rather than months. With Adalo's visual builder, you can create a fully functional Duolingo clone complete with lesson progression, achievements, and user profiles—all without writing a single line of code.

Why Adalo Works for Building a Language Learning App

Adalo is a no-code app builder for database-driven web apps and native iOS and Android apps—one version across all three platforms, published to the Apple App Store and Google Play. This makes it the perfect choice for creating a Duolingo-style language learning app, where users expect a seamless native experience with offline capabilities, smooth animations, and responsive interactions across their devices.

For language learning apps specifically, app store distribution is crucial—learners want to download from trusted sources and receive push notifications that remind them to maintain their daily streaks. With Adalo, you can build once and reach millions of potential users on both major app marketplaces, complete with native push notification support to keep your learners engaged and coming back for their daily lessons.

This comprehensive tutorial will walk you through creating a fully functional language learning app using Adalo's no-code platform. You'll build features including lesson progression, progress tracking, streaks, achievements, and user profiles. Adalo's agnostic builder lets you publish the same app to the web, native iOS, and native Android, all without writing a line of code or rebuilding. If your plan is mass distribution through the app stores vast marketplaces, then this is a great option versus many of the vibe-coding builders out there today.

Prerequisites and Initial Setup

Step 1: Create Your Adalo Account and App

1. Go to Adalo.com and sign up
2. Click "Create New App"
3. Choose "Mobile App" (recommended for language learning)
4. Name your app (e.g., "LanguageMaster")
5. Select "Start from Scratch" (no language learning templates available)

Step 2: Set Your App Theme

1. Choose a primary color (e.g., green like Duolingo)
2. Select a secondary color (e.g., blue for progress elements)
3. Pick a clean, readable font
4. Click "Continue" to enter the editor

Building the Database Structure

Step 3: Enhance the Users Collection

1. Click the Database icon in left sidebar
2. Click on "Users" collection (already exists)
3. Add these properties (click "+ Add Property" for each):
   
   • Current Language (Text)
   • Total XP (Number) - Default: 0
   • Current Streak (Number) - Default: 0
   • Last Activity Date (Date & Time)
   • Profile Image (Image)
   • Learning Goal (Text) - Values: "Casual", "Regular", "Serious", "Intense"
   • Preferred Study Time (Text)
   • Sound Effects Enabled (True/False) - Default: True
   • Push Notifications Enabled (True/False) - Default: True
   • League (Text) - Default: "Bronze"

Learn more about databases

Step 4: Create the Languages Collection

1. Click "+ Add Collection"
2. Name it "Languages"
3. Add these properties:
   
   • Language Name (Text)
   • Language Code (Text) - e.g., "ES", "FR", "DE"
   • Flag Image (Image)
   • Total Lessons (Number)
   • Difficulty Level (Text) - Values: "Beginner", "Intermediate", "Advanced"
   • Description (Text - Multiline)
   • Is Active (True/False) - Default: True

Step 5: Create the Courses Collection

1. Click "+ Add Collection"
2. Name it "Courses"
3. Add properties:
   
   • Course Name (Text)
   • Description (Text - Multiline)
   • Order Number (Number)
   • Total Lessons (Number)
   • Course Icon (Image)
   • Unlock Requirement (Number) - XP needed to unlock
   • Is Unlocked (True/False) - Default: False

Step 6: Create the Lessons Collection

1. Click "+ Add Collection"
2. Name it "Lessons"
3. Add properties:
   
   • Lesson Title (Text)
   • Order Number (Number)
   • XP Reward (Number) - Default: 10
   • Estimated Time (Number) - In minutes
   • Lesson Type (Text) - Values: "Vocabulary", "Grammar", "Speaking", "Listening"
   • Unlock Requirement (Number) - Previous lessons needed
   • Is Story (True/False) - Default: False
   • Icon Image (Image)

Step 7: Create the Questions Collection

1. Click "+ Add Collection"
2. Name it "Questions"
3. Add properties:
   
   • Question Text (Text - Multiline)
   • Question Type (Text) - Values: "Multiple Choice", "Translation", "Listening", "Speaking", "Match"
   • Correct Answer (Text)
   • Wrong Option 1 (Text)
   • Wrong Option 2 (Text)
   • Wrong Option 3 (Text)
   • Audio File (File)
   • Image (Image)
   • Explanation (Text - Multiline)
   • Difficulty (Number) - 1-5 scale

Step 8: Create the UserProgress Collection

1. Click "+ Add Collection"
2. Name it "UserProgress"
3. Add properties:
   
   • Completion Date (Date & Time - Automatic)
   • Score (Number) - Percentage 0-100
   • Time Spent (Number) - In seconds
   • Mistakes Made (Number)
   • XP Earned (Number)
   • Perfect Lesson (True/False) - Default: False
   • Hearts Lost (Number)

Step 9: Create the Achievements Collection

1. Click "+ Add Collection"
2. Name it "Achievements"
3. Add properties:
   
   • Badge Name (Text)
   • Badge Image (Image)
   • XP Required (Number)
   • Description (Text - Multiline)
   • Category (Text) - Values: "Streak", "XP", "Lessons", "Perfect"
   • Is Earned (True/False) - Default: False
   • Earned Date (Date & Time)

Step 10: Create the UserAnswers Collection

1. Click "+ Add Collection"
2. Name it "UserAnswers"
3. Add properties:
   
   • User Answer (Text)
   • Is Correct (True/False)
   • Answered Date (Date & Time - Automatic)
   • Time Taken (Number) - In seconds
   • Hint Used (True/False) - Default: False

Step 11: Set Up Database Relationships

In Languages collection:

• Add relationship to Courses: One-to-Many

In Courses collection:

• Add relationship to Languages: Many-to-One
• Add relationship to Lessons: One-to-Many

In Lessons collection:

• Add relationship to Courses: Many-to-One
• Add relationship to Questions: One-to-Many
• Add relationship to UserProgress: One-to-Many

In Questions collection:

• Add relationship to Lessons: Many-to-One
• Add relationship to UserAnswers: One-to-Many

In UserProgress collection:

• Add relationship to Users: Many-to-One
• Add relationship to Lessons: Many-to-One

In UserAnswers collection:

• Add relationship to Users: Many-to-One
• Add relationship to Questions: Many-to-One
• Add relationship to UserProgress: Many-to-One

In Achievements collection:

• Add relationship to Users: Many-to-Many

Installing Required Components

Step 12: Install Progress Components

1. Go to Adalo Marketplace
2. Search for "Progress Bar"
3. Click "Install" on the Progress Bar component
4. Search for "Countdown Timer" and install
5. Search for "Confetti" and install for celebrations

Step 13: Install Audio Components

1. In Marketplace, search "Audio Player"
2. Install the Audio Player component
3. Search for "Text to Speech" if available
4. Return to your app editor

Step 14: Install Animation Components

1. Search for "Lottie" in Marketplace
2. Install Lottie animations for loading states
3. Search for "Skeleton" for loading placeholders
4. Install any celebration animation components

Creating User Authentication and Onboarding

Step 15: Build the Welcome Screen

1. On the default screen, rename it to "Welcome"
2. Add an Image for your app logo
3. Add Text: "Learn languages for free"
4. Add Text: "Learn with bite-sized lessons based on science"
5. Add two Buttons:
   
   • "Get Started" → Link to new screen "Language Selection"
   • "I Already Have an Account" → Link to new screen "Login"

Step 16: Create Language Selection Screen

1. Add new screen "Language Selection"
2. Add Text: "I want to learn..."
3. Add Custom List component:
   
   • Connect to Languages collection
   • Show: Flag Image, Language Name, Difficulty Level
   • Make each item clickable
4. Add action on item click:
   
   • Update Logged In User → Current Language
   • Link to "Goal Setting" screen

Step 17: Create Goal Setting Screen

1. Add new screen "Goal Setting"
2. Add Text: "How much time do you want to spend learning?"
3. Add Button Grid with options:
   
   • "Casual - 5 min/day"
   • "Regular - 10 min/day"
   • "Serious - 15 min/day"
   • "Intense - 20 min/day"
4. Each button updates User → Learning Goal
5. Navigate to "Sign Up" screen

Step 18: Create Sign Up Screen

1. Add new screen "Sign Up"
2. Add Form component:
   
   • Connect to Users collection
   • Include fields: Email, Password, Full Name
   • Add Image Picker for Profile Image
3. Add submit action:
   
   • Create User account
   • Initialize Current Streak = 0, Total XP = 0
   • Link to "Home" screen
4. Add Google Sign-In option

Step 19: Create Login Screen

1. Add new screen "Login"
2. Add text input components:
   
   • Email input
   • Password input
3. Add "Login" button with login action
4. Add "Forgot Password?" text → Link to password reset
5. Navigate to "Home" on successful login

Building the Main App Interface

Step 20: Create Home Screen with Tab Navigation

1. Add new screen "Home"
2. Set up bottom tab navigation with 4 tabs:
   
   • Learn (Home icon)
   • Stories (Book icon)
   • Profile (Person icon)
   • Leaderboard (Trophy icon)

Step 21: Build the Learn Tab (Home Dashboard)

1. Add user greeting section:
   
   
   
   • Text: "Hi [Logged In User Name]!"
   • Show current streak with fire icon
   • Display total XP earned
2. Add daily goal progress:
   
   
   
   • Progress Bar component
   • Connect to user's daily XP progress
   • Show XP earned today / daily goal
3. Add course selection section:
   
   
   
   • Text: "Choose your course"
   • Custom List of courses:
     
     • Filter: Language = Logged In User Current Language
     • Show: Course Icon, Course Name, Progress %
     • Enable click action → Link to "Lesson List" screen
4. Add quick practice section:
   
   
   
   • Button: "Practice" → Random review questions
   • Button: "Stories" → Navigate to Stories tab

Step 22: Create Lesson List Screen

1. Add new screen "Lesson List"
2. Add header with course name and overall progress
3. Add Progress Bar for course completion
4. Add Custom List of lessons:
   
   • Connect to Lessons collection
   • Filter: Course = Current Course (passed as parameter)
   • Sort by: Order Number
5. For each lesson card, show:
   
   • Lesson number and title
   • XP reward value
   • Completion status (checkmark if completed)
   • Lock icon if not yet unlocked
6. Add conditional actions:
   
   • If lesson is unlocked → Link to "Practice" screen
   • If lesson is locked → Show "Complete previous lessons" message

Implementing the Practice/Lesson System

Step 23: Create Practice Screen

1. Add new screen "Practice"
   
   
2. Add top navigation bar showing:
   
   
   
   • Close button (X) → Confirm exit dialog
   • Progress Bar showing lesson progress
   • Hearts remaining (start with 5)
3. Add question display section:
   
   
   
   • Text: Current Question → Question Text
   • Image: Current Question → Image (conditional visibility)
   • Audio Player: Current Question → Audio File (conditional visibility)
4. Add answer section (varies by question type):
   
   
   
   • For Multiple Choice: Button list with options
   • For Translation: Text Input field
   • For Listening: Multiple choice after audio
   • For Speaking: Record button (if available)

Step 24: Build Question Logic System

1. Create custom action for answer checking:
   
   
   
   • Compare user answer with correct answer
   • Create UserAnswers record
   • Update score and progress
   • Show feedback (correct/incorrect)
2. Add feedback section:
   
   
   
   • Green background for correct answers
   • Red background for incorrect answers
   • Show correct answer for wrong responses
   • Display explanation text
3. Add progression logic:
   
   
   
   • On correct: Move to next question
   • On incorrect: Lose a heart, show correct answer
   • If hearts = 0: End lesson, show results
   • If all questions completed: Calculate final score

Step 25: Create Question Types

Multiple Choice Questions:

1. Display question text
2. Show 3-4 answer buttons
3. Highlight selected answer
4. Check answer on submit
5. Show correct answer in green

Translation Exercises:

1. Show source text to translate
2. Add text input for answer
3. Add hint button (shows first letter)
4. Accept variations of correct answer
5. Use word bank as alternative input

Listening Comprehension:

1. Add Audio Player component
2. Show replay button (limited uses)
3. Display question after audio
4. Provide multiple choice answers
5. Show transcript after completion

Step 26: Build Lesson Results Screen

1. Add new screen "Lesson Results"
   
   
2. Display lesson summary:
   
   
   
   • XP earned (based on score)
   • Accuracy percentage
   • Time taken
   • Mistakes made
3. Add celebration elements:
   
   
   
   • Confetti animation for perfect scores
   • Crown icon for lesson mastery
   • Streak maintenance message
4. Add action buttons:
   
   
   
   • "Continue" → Next lesson or back to course
   • "Review Mistakes" → Show incorrect answers
   • "Practice Again" → Restart lesson

Implementing Progress Tracking

Step 27: Create Streak Calculation Logic

1. Build custom action for daily activity:
   
   
   
   • Check if Last Activity Date = Today
   • If yes: Don't update streak
   • If yesterday: Increment Current Streak
   • If gap > 1 day: Reset Current Streak to 1
   • Update Last Activity Date to today
2. Add streak display components:
   
   
   
   • Fire icon with streak number
   • Encouraging messages for milestones
   • Streak freeze options (premium feature)

Step 28: Build XP and Leveling System

1. Create XP calculation rules:
   
   
   
   • Base XP per correct answer: 5 points
   • Perfect lesson bonus: 50% extra XP
   • Speed bonus: Extra XP for quick completion
   • Daily goal bonus: 20 XP for meeting goal
2. Add level progression:
   
   
   
   • Create level thresholds (0, 100, 250, 500, 1000, etc.)
   • Calculate current level from Total XP
   • Show progress to next level
   • Display level badges in profile

Step 29: Create Achievement System

1. Build achievement tracking:
   
   
   
   • Check achievements after each lesson
   • Award badges for milestones
   • Show notification for new achievements
   • Update Achievements collection
2. Achievement categories:
   
   
   
   • Streak achievements (3, 7, 30, 100 days)
   • XP milestones (500, 1000, 5000 XP)
   • Perfect lesson streaks
   • Course completion badges

Building User Profile and Settings

Step 30: Create Profile Screen

1. Add user info section:
   
   
   
   • Profile image
   • User name and current level
   • Total XP and current streak
   • Learning goal progress
2. Add statistics section:
   
   
   
   • Days learning
   • Lessons completed
   • Average accuracy
   • Time spent learning
3. Add achievements showcase:
   
   
   
   • Grid of earned badges
   • Progress toward next achievements
   • Share buttons for milestones

Step 31: Build Settings Screen

1. Add account settings:
   
   
   
   • Change profile picture
   • Update learning goal
   • Change target language
   • Notification preferences
2. Add app preferences:
   
   
   
   • Sound effects toggle
   • Push notification settings
   • Reminder time picker
   • Offline download options
3. Add support section:
   
   
   
   • Help center link
   • Contact support
   • Privacy policy
   • Terms of service

Implementing Social Features

Step 32: Create Leaderboard Screen

1. Add weekly league standings:
   
   
   
   • List users in same league
   • Show XP earned this week
   • Display rank and position changes
   • Add promotion/demotion indicators
2. Add friend features:
   
   
   
   • Friend list with activity
   • Add friend by username
   • Compare progress
   • Send encouragement

Step 33: Build Stories Feature

1. Create Stories screen:
   
   
   
   • List of unlocked stories
   • Progress indicators
   • Difficulty levels
   • Character introductions
2. Add story reading interface:
   
   
   
   • Text with translations
   • Audio narration
   • Comprehension questions
   • Vocabulary highlights

Adding Advanced Features

Step 34: Implement Offline Mode

1. Add download functionality:
   
   
   
   • Download lessons for offline use
   • Cache audio files
   • Store progress locally
   • Sync when connection returns
2. Add offline indicators:
   
   
   
   • Show download status
   • Indicate offline availability
   • Queue actions for sync

Step 35: Create Review System

1. Build spaced repetition:
   
   
   
   • Track word difficulty
   • Schedule review sessions
   • Focus on weak areas
   • Adaptive difficulty
2. Add practice modes:
   
   
   
   • Timed challenges
   • Mistake review
   • Weak skills practice
   • Speaking practice

Step 36: Implement Gamification

1. Add virtual currency:
   
   
   
   • Earn gems for achievements
   • Shop for power-ups
   • Streak freezes
   • Extra hearts
2. Create challenges:
   
   
   
   • Weekly challenges
   • Friend competitions
   • Global events
   • Special rewards

Setting Up Notifications

Step 37: Configure Push Notifications

1. Request notification permission on first launch
   
   
2. Set up reminder types:
   
   
   
   • Daily practice reminders
   • Streak maintenance alerts
   • Achievement notifications
   • Weekly progress summaries
3. Implement notification scheduling:
   
   
   
   • Based on user's preferred time
   • Streak risk warnings
   • Achievement celebrations
   • Course updates

Learn about notifications

Testing Your Language Learning App

Step 38: Add Test Data

1. Create sample content:
   
   
   
   • 2-3 languages with courses
   • 10-15 lessons per course
   • 50+ questions with various types
   • Audio files for listening exercises
2. Create test user accounts:
   
   
   
   • Different experience levels
   • Various learning goals
   • Multiple language preferences

Step 39: Test Core Learning Flow

1. Complete onboarding process
2. Take lessons and verify XP calculation
3. Test all question types
4. Verify progress tracking accuracy
5. Check streak calculation logic
6. Test offline functionality

Step 40: Test Social Features

1. Add friends and compare progress
2. Verify leaderboard updates
3. Test achievement triggers
4. Check notification delivery
5. Validate story unlock logic

Working with Limitations

Step 41: Handle Real-Time Features

Since Adalo has limited real-time capabilities:

1. Use refresh actions to update data
2. Set automatic refresh intervals
3. Use countdown timers for timed exercises
4. Implement manual sync buttons

Step 42: Optimize Performance

1. Use filtered lists to reduce data loading
2. Implement pagination for large content sets
3. Cache frequently accessed data
4. Optimize image sizes for mobile

Publishing and Launch Preparation

Step 43: Prepare for App Store Submission

1. Create app store screenshots
2. Write compelling app descriptions
3. Set up app store optimization
4. Prepare privacy policy
5. Configure app settings for iOS/Android

Step 44: Set Up Analytics and Monitoring

1. Implement user behavior tracking
2. Monitor lesson completion rates
3. Track user retention metrics
4. Set up crash reporting
5. Monitor server performance

Step 45: Plan Content Updates

1. Create content creation workflow
2. Plan regular lesson additions
3. Schedule seasonal events
4. Design feedback collection system
5. Prepare community features

Resources for Continued Learning

• Adalo Component Basics
• Database Best Practices
• Marketplace Components
• Adalo YouTube Tutorials
• App Templates

Note: This Duolingo clone will have some limitations compared to the native Duolingo app, particularly in advanced AI features and complex speech recognition. However, it provides an excellent foundation for a language learning app that can effectively teach languages through structured lessons, progress tracking, and gamification elements.

FAQ