Cost to Build a Language Learning App Like Duolingo in 2026

What a Duolingo-style app includes

Duolingo turns a language course into short, game-like lessons with a habit loop around them: a daily streak, points, leagues and reminders. The code behind a single lesson is not hard. The cost comes from the lesson engine that supports many exercise types, the scheduling that decides what to review next, the content tooling that lets a course team write and maintain thousands of items, and the habit features that keep people coming back.

• Learner app: course and unit map, lessons with several exercise types, hearts or energy, progress and mastery, streaks, leaderboards, friends, reminders, subscriptions.
• Learning engine: item bank, lesson assembly, spaced repetition scheduling, mistake tracking, placement test.
• Content tools: course authoring, versioning, audio recordings, translations, review workflow.
• Platform: accounts and social login, analytics, A/B testing hooks, admin.

Language learning app development cost: MVP vs full product

What the first release covers

The calculator setup is a mobile app with a premium design, because a learning product lives or dies on how the exercises feel and the animation and motion work is real effort. It includes:

• User accounts and roles for learners, content editors and admins.
• Social or SSO login with Apple and Google.
• Lessons, quizzes and progress: the lesson engine, exercise types, mastery and review scheduling.
• Subscriptions and billing through in-app purchase, with a free tier and a paid tier.
• Push and email notifications for streak reminders and lesson nudges.
• Offline mode and sync, so downloaded units work on a train and progress syncs later.
• Social feed and comments, used here for leaderboards, friends and weekly leagues.
• Admin panel for course authoring, audio uploads and publishing.
• Dashboards and reports: completion, retention, difficulty per item.
• One third-party integration: speech recognition for speaking exercises.

Cost by feature

Hours include design, development and testing for each component. Costs apply our blended rate of $28 to $38 an hour, and the headline range allows plus or minus 15 percent on hours. Open this setup in the calculator to change it.

The lesson engine and spaced repetition

Design the item bank first. Every exercise is an item with a type, a prompt, accepted answers, distractors, audio, hints and tags for the grammar or vocabulary it teaches. Lessons are then assembled from items rather than written as fixed scripts, which is what lets you add exercise types later without rewriting courses. Start with five or six types: multiple choice, translate by tapping words, type the answer with fuzzy matching, listen and type, match pairs, and speak.

Spaced repetition decides when each item comes back. The classic SM-2 algorithm from SuperMemo is simple to implement and good enough for an MVP; newer open-source schedulers such as FSRS fit review intervals to each learner's history and can replace it later without changing the data model. The important design choice is to store every answer event, because that history is what the scheduler, the analytics and any future personalisation all run on.

Streaks, leaderboards and reminders

The habit loop is cheap to build and expensive to get wrong. A streak needs a clear rule for the day boundary across time zones, a freeze mechanic, and a reminder that fires at the time the learner usually studies. Leaderboards need weekly cohorts, promotion and relegation between leagues, and protection against bots that farm points. Build these on the same event stream as the lesson engine and keep the rules in configuration so product can tune them without a release.

Speech recognition for speaking exercises

Pronunciation exercises use a speech-to-text service and compare the transcript to the expected sentence. On-device recognition from Apple and Google is free but uneven across languages. Cloud services are more consistent and bill per minute of audio; Deepgram's Nova-3 streaming model, for example, is listed at $0.0048 per minute on promotion and $0.0077 at the regular rate on its pricing page, checked October 2026. A speaking exercise is a few seconds of audio, so the per-learner cost is small, but keep speaking exercises optional in the MVP and measure how many people use them before investing in phoneme-level scoring.

Subscriptions and app store fees

A learning app sells a digital subscription, so it must use in-app purchase on iOS and Google Play billing on Android. Apple's standard commission is 30 percent, reduced to 15 percent for developers in the App Store Small Business Program; Google Play's service fee is 15 percent on the first $1 million of annual revenue. Both are published on the stores' own pages and apply to every subscription you sell in the app. A subscription-management service such as RevenueCat saves weeks of receipt validation and renewal handling and is worth the fee for most teams.

Content tooling is a product of its own

The admin panel in the estimate is where course authors work, and it is easy to under-scope. A course of a few hundred lessons has thousands of items, each with audio, and a team editing them needs drafts, review, versioning and the ability to publish a fix without shipping an app update. We built the quiz engine behind the StoryLearning widget with six question types, audio playback and fuzzy answer matching that forgives typos, and the content model there, courses to lessons to items, is the same shape a full learning app needs.

What it costs to run each month

• App store commissions on every subscription, as above.
• Speech-to-text minutes and text-to-speech for generated audio, both billed per use.
• Audio and image storage with a CDN, since every item ships a sound file.
• Push notifications and email at scale, where reminders are the main driver.
• Hosting, analytics, a subscription service and a maintenance retainer of $1.5k to $8k per month.

Where the budget can be cut

1. Launch one language pair and one course, written before the app is finished.
2. Build the item bank and five exercise types; add speaking and writing exercises after launch.
3. Use SM-2 scheduling and replace it with FSRS when you have review data.
4. Use a subscription-management service rather than hand-rolling receipt validation.
5. Build the app in Flutter so iOS and Android share one codebase and one animation layer.

We build learning products for the education sector, from LMS platforms to embeddable quiz widgets, and ship mobile apps with Flutter. See also our guide to mobile app development cost in 2026.

Sources

• Innovation Insight app development cost calculator and pricing
• SuperMemo, the SM-2 algorithm: https://super-memory.com/english/ol/sm2.htm
• Open Spaced Repetition, FSRS: https://github.com/open-spaced-repetition/fsrs4anki
• Deepgram pricing (checked October 2026): https://deepgram.com/pricing
• Apple App Store Small Business Program: https://developer.apple.com/app-store/small-business-program/
• Google Play service fees: https://support.google.com/googleplay/android-developer/answer/112622
• Innovation Insight, StoryLearning quiz widget case study and LMS development