Language Learning App Development

Duolingo offers you the fantasy of speaking a new language. Learners feel like they're learning to answer its questions, not learning the language. Think of Duolingo as a fun introduction, a springboard for serious language learning. Your school, your platform, your tutor network is what comes after the springboard. Built for edtech founders, corporate training providers, and tutoring marketplace operators whose learning experience, adaptive content engine, or integration requirements have outgrown generic LMS platforms and white-label course tools. When your differentiation lives in how learners progress, how tutors are matched, or how speech is assessed, a standard platform will always compromise the product.

  • Adaptive lesson engines that sequence content based on each learner's proficiency, error patterns, and session history

  • AI speech recognition and pronunciation scoring using Google Cloud Speech-to-Text, Azure Cognitive Services, or custom acoustic models

  • Spaced repetition systems (SRS) built on SM-2 or custom algorithms that surface vocabulary and grammar at the optimal review interval

  • Live tutor marketplace with calendar-based booking, session management, Zoom or Daily.co video integration, and payout automation via Stripe Connect

The problem

Sound familiar?

  • Stuck on an LMS that handles your content delivery but can't support adaptive sequencing, pronunciation scoring, or live tutor booking without bolting on five separate tools?

  • Learner drop-off climbing because your platform pushes everyone through the same lesson path regardless of proficiency, pace, or how they've been performing?

  • Corporate clients asking for SCORM exports, SSO, and HR system integration that your current platform either doesn't support or charges you a per-seat premium to unlock?

Short answer

RaftLabs handles language learning app development for edtech startups, corporate training providers, and tutoring marketplace operators. We ship adaptive lesson engines, AI speech recognition and pronunciation scoring, spaced repetition systems, and live tutor booking platforms. Most teams launch a validated MVP in 12 to 16 weeks at a fixed, agreed cost, then iterate from there.

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01 Diagnosis

Where language learning businesses actually leak

  1. 01
    Problem

    Your platform pushes every learner through the same lesson path

    Solution

    When every learner follows an identical sequence regardless of what they already know, two things happen: advanced learners disengage in the early modules, and struggling learners fall behind and drop off without intervention. Neither group finishes. Adaptive spaced repetition paired with AI pronunciation feedback holds learners better than a static lesson sequence, because review timing and difficulty track each learner instead of an assumed average.The fix is an adaptive engine that reads each learner's performance at the session level, identifies gaps in vocabulary and grammar, and selects the next content item accordingly. Combined with spaced repetition scheduling built on algorithms like SM-2, vocabulary resurfaces at the optimal review interval rather than in a fixed weekly cycle. The outcome is a learner path that tightens around each user's actual needs, not an assumed average.

  2. 02
    Problem

    Most apps fail at real speaking practice

    Solution

    Most language apps focus on grammar and vocabulary but fail at real speaking practice. Pronunciation is the hardest skill to teach at scale because it requires real-time, accurate feedback on sounds the learner can't yet hear. Most language platforms either skip speech assessment entirely, rely on basic keyword spotting that passes near-misses, or integrate a third-party tool that produces a score with no explanatory feedback. Learners practice speaking, get a thumbs-up, and form incorrect habits for months.Accurate speech assessment requires integrating purpose-built acoustic models through APIs like Google Cloud Speech-to-Text, Azure Cognitive Services Speech SDK, or specialist providers like SoapBox Labs for children's speech. On top of transcription, pronunciation scoring needs phoneme-level comparison, fluency scoring based on pace and pausing, and feedback the learner can act on. The gap between a score that appears and a score the learner trusts is where retention is won or lost.

  3. 03
    Problem

    Retention is the growth strategy, and nobody flags the at-risk learner

    Solution

    The most foundational way to grow an online school is to not lose the business you already have. Students quit at predictable danger years, and the cause is lost priority, not lesson quality. Parents start asking what the learning is leading to. By junior high, the question is direct: will this help at school, with exams, or in the future?A platform that tracks engagement signals, flags at-risk learners before families decide, and surfaces progress toward the parent's actual goal keeps the student enrolled. The outcome is retention that compounds, not replacement marketing that bleeds.

  4. 04
    Problem

    Your tutor marketplace is too manual to scale

    Solution

    Tutoring marketplace operators running tutor matching, session booking, and lesson payment through email, spreadsheets, and manual bank transfers hit a ceiling that has nothing to do with learner demand. Tutor no-shows and late cancellations leak revenue, and enforcing the policy feels awkward. The administrative overhead per session stays fixed while the margin per session shrinks as tutor supply grows. The bottleneck is the back office, not the market.A purpose-built tutor marketplace automates the matching logic, surfaces tutor availability through calendar integration, handles session booking and reminders, runs video sessions through Zoom or Daily.co, and pays tutors automatically on schedule via Stripe Connect. No-show and late-cancellation policies enforce automatically through the platform, so nobody has to have the awkward conversation. The outcome is unit economics that work at scale.

02 What we ship

Language learning software we build

  1. Adaptive lesson engines

    We build lesson sequencing engines that track learner performance at the item level, across vocabulary, grammar, reading, and listening, and select the next content item based on accuracy, response time, and error patterns. The engine is built to your pedagogical model: whether that is proficiency-band progression, topic-first sequencing, or a hybrid approach for mixed-level corporate cohorts.

    Spaced repetition scheduling based on SM-2 or a custom interval algorithm surfaces vocabulary at the optimal review point for each learner rather than at a fixed calendar date. The scheduling parameters are configurable, so your content team can tune review density for high-priority exam vocabulary or low-frequency business terms.

    Built for edtech startups building a differentiated learning product, corporate training providers replacing static course libraries, and language schools moving their curriculum to a digital adaptive format.

  2. AI speech recognition and pronunciation scoring

    We integrate Google Cloud Speech-to-Text, Azure Cognitive Services Speech SDK, and specialist providers like SoapBox Labs to deliver real-time transcription and pronunciation assessment inside your app. On top of transcription, we build phoneme-level scoring, fluency analysis based on pace and pausing, and feedback that tells the learner which sounds to correct, not just a pass-fail score.

    The speech layer is calibrated for your target language and learner profile. Accent variation handling, background noise tolerance thresholds, and confidence score tuning are configured for the specific population using the app. Children's speech, non-native accents, and low-bandwidth conditions each require different calibration, and we scope that during discovery.

    Built for language learning apps where pronunciation is a core learning objective, corporate English training providers, and edtech companies building a speak-first curriculum.

  3. Spaced repetition and vocabulary systems

    We build vocabulary and grammar review systems on spaced repetition algorithms that surface items at the interval most likely to consolidate long-term memory. The interval logic is implemented as a first-class system, not a static quiz scheduler, so each learner's review queue reflects their actual retention curve across every item they've encountered.

    Content management for vocabulary systems includes bulk import from CSV or structured data sources, tagging by topic, difficulty, and grammar category, and learner-facing decks for self-study alongside system-generated review queues. Word frequency lists, CEFR-level tagging, and custom content libraries for specialist vocabulary are all configurable by your content team without a developer.

    Built for language learning apps with large vocabulary curricula, exam preparation platforms, and corporate language training tools where learners need to acquire domain-specific business vocabulary quickly.

  4. Live tutor marketplace platforms

    We build end-to-end tutor marketplace platforms: tutor onboarding and profile management, learner-facing search and matching, calendar-based session booking with timezone handling, live video via Zoom SDK or Daily.co, and automated tutor payouts via Stripe Connect. The matching rules, availability management, and commission structure are built to your business model.

    Session management covers booking confirmations, pre-session reminders, cancellation and rescheduling policies, and post-session review collection. Dispute handling, refund workflows, and tutor performance scoring run without manual case management. Reporting dashboards give marketplace operators visibility into session volume, tutor utilisation, and learner retention at the cohort level.

    Built for tutoring marketplace operators replacing manual coordination, language schools adding live 1-on-1 sessions to a self-paced product, and corporate training providers building a managed tutor network.

  5. Progress tracking and analytics dashboards

    We build learner-facing progress dashboards that show vocabulary acquisition, lesson streak data, skill-level progression across speaking, listening, reading, and writing, and time-to-goal projections based on current pace. The data surfaces at the learner level to keep individuals engaged and at the cohort level for instructors and training managers.

    Corporate training dashboards give L&D managers visibility into completion rates, proficiency gains, and learner activity across teams and departments. Progress data exports to CSV or pushes via API to HRIS and LMS platforms. Completion certificates with CEFR level assessments are generated automatically and delivered to the learner's profile and the corporate training record.

    Built for corporate language training providers, tutoring marketplace operators tracking learner outcomes, and edtech companies that need to demonstrate measurable learning gains to enterprise procurement teams.

  6. Corporate training integrations and enterprise features

    We build the integration layer that lets enterprise buyers deploy your platform inside their existing systems. SAML 2.0 and OAuth SSO connect your app to identity providers including Okta, Azure Active Directory, and Google Workspace, so employees log in with their company credentials. SCORM 1.2 and xAPI content packages let you export lessons and completion data into any corporate LMS.

    REST API webhooks push progress events, completion records, and proficiency scores into HRIS platforms like Workday, BambooHR, and SAP SuccessFactors. Multi-tenant architecture isolates each corporate client's data, admin permissions, and branding. Bulk user provisioning via SCIM handles roster changes without manual account management.

    Built for language learning platforms entering enterprise sales, corporate training providers integrating with large employers' tech stacks, and edtech companies whose commercial growth depends on passing enterprise security and compliance reviews.

03 Buy, build, or wait

The language learning software question is really about whether the platform teaches the language, or the fantasy.

Buy or rent

  • Teachable or TalentLMS, for course delivery

    Right when your differentiator is content, not technology. Standard delivery to a small audience.

  • Duolingo, for the learner

    A fun introduction, a springboard for serious language learning. Not your competitor; your feeder.

Build custom

  • When you are the springboard's destination

    Learners outgrow the fantasy when they want real conversation. Your product is what comes after.

  • When apps fail at real speaking practice

    Grammar and vocabulary drills don't teach pronunciation. Real speech assessment, calibrated for your learners.

  • When retention is the business

    Not losing the business you already have. At-risk flags before the family decides to leave.

Bottom line

Stay on the platform while the product is standard course delivery. Build when the adaptive engine, the speech assessment, or the tutor marketplace is the product.

04 How we work

How we build language learning products

  1. 01

    Discovery

    We map your pedagogical model, learner profile, and the content and integration requirements in detail. We identify where your current platform creates product limitations or operational overhead. For language learning products, we scope the speech assessment calibration requirements, the adaptive engine logic, and the LMS or HRIS integrations your corporate clients need. The risk this retires: the pedagogy the template assumed.
  2. 02

    Design

    We design the learner experience, the content management system your team will use to author and update lessons, and the data model underneath the adaptive engine. For tutor marketplace products, we design the matching logic, the booking flow, and the payout architecture before writing production code. The risk this retires: the scope that surprises mid-build.
  3. 03

    Build

    We build in two-week cycles with working software at each checkpoint. The core lesson engine and learner data model ship first. Speech recognition integration, spaced repetition scheduling, and the admin dashboard follow in subsequent cycles. The risk this retires: the integration bolted on at the end.
  4. 04

    Launch

    We go live with a controlled cohort before full release. Speech assessment calibration is validated against real learner audio. Corporate SSO and LMS integration is tested end-to-end with the first enterprise client's IT team before the contract goes live. The risk this retires: the go-live that misses the first school term.

05 Track record

What language learning businesses get when they work with us

Weeks to a validated language learning MVP
12-16
Shipping production edtech and consumer software
Since 2015
Cost agreed before development starts
Fixed

Edtech and learning products we have shipped

We do not have a public language learning app we can name here, so read this as adjacent proof. The learning mechanics carry across.

For Sekou, a school network in West Africa, we built a learning management system from concept to launch in 16 weeks, with a data model that supports 4,000 or more students per school. For TuneClub, a music-learning platform, we built structured practice pathways and creator feedback loops that logged 200 or more practice sessions in the first 60 days. For Eris Lifesciences, we built EMS Connect, a corporate training platform that reached 3,500 or more daily active users and cut training time by 25%.

Adaptive sequencing, spaced practice, speech and media handling, and corporate learning and development reporting are the same building blocks a language product needs. That is the work we bring to a language learning build.

08 Why us

Why choose us?

  • 01

    We've seen your problem before

    Across dozens of industries, we recognise your situation fast, then frame the fix around your margin and your operations, not a generic template.
  • 02

    We own the number, not the ticket

    We measure success the way you do: hours saved, revenue earned, margin recovered. We stay through launch and growth, so the result is ours to own.
  • 03

    Serious businesses trust us

    Vodafone, T-Mobile, Cisco, Energia, Aldi, Nike. Building since 2015. Serious businesses keep coming back because we stay accountable long after launch.

09 Questions

Common questions

Yes. Building the adaptive layer, proprietary speech scoring, or tutor matching logic on top of or alongside an existing platform is a specific type of engagement we take on. During discovery we scope exactly what needs to be built custom versus what can stay on the existing system. The outcome is a working integration, not a full platform rebuild.

Yes. We build adaptive engines that track per-learner proficiency across vocabulary, grammar, and speaking, then select and sequence content based on error patterns, time-on-task, and spaced repetition schedules. The sequencing logic is built to your pedagogical model. We also build the content management layer so your curriculum team can add or update lessons without a developer.

An MVP covering adaptive lessons, progress tracking, and basic speech assessment typically delivers in 12 to 16 weeks. Cost depends on scope. A full platform with a live tutor marketplace, AI speech recognition, corporate SSO, and SCORM export depends on integration complexity and the number of languages supported. Fixed cost is agreed before development starts.

Yes. We build SCORM 1.2 and xAPI exports for LMS compatibility, SAML 2.0 and OAuth SSO for enterprise identity providers including Okta and Azure Active Directory, and REST API integrations with HRIS platforms like Workday and BambooHR. SCIM-based user provisioning handles bulk roster changes. Corporate integrations are scoped during discovery and designed into the architecture from the start, not added after go-live.

You don't compete with it; you follow it. Duolingo is a springboard for serious language learning, not the destination. Learners outgrow the fantasy when they want real conversation. Your product wins on what the free app can't deliver: real speaking practice with human feedback, structured progress toward a goal (exam, job, relocation), and accountability from a tutor or cohort. We build the software that proves those outcomes: pronunciation scoring, progress dashboards, and the tutor marketplace that turns motivation into retention.

Off-the-shelf platforms like Teachable, Thinkific, or TalentLMS are the right call when your product is standard course delivery and your differentiator is your content, not your technology. Custom development makes sense when your differentiation is in adaptive sequencing, proprietary speech assessment, a live tutor marketplace, or an enterprise integration stack that no platform supports without heavy per-seat fees. We scope the build-versus-extend decision during discovery so you invest in the right thing at the right time.

In most cases, AI speech recognition can be added to an existing product without a full rebuild. We integrate Google Cloud Speech-to-Text, Azure Cognitive Services Speech SDK, or specialist providers depending on the language, learner age group, and accuracy requirements. The integration scope, API wiring, audio capture pipeline, and scoring display layer, is typically a 4 to 8 week addition. We assess the existing codebase during discovery and give a fixed scope before work starts.

Get a build-vs-Teachable plan for your learning product

Tell us what you are building and we will scope it out together.

  • Scope and cost agreed before work starts. No surprises. No obligation.
  • Working prototype within 3 weeks of kickoff.
  • Pay by milestone. You see progress before each invoice.
  • 60-day post-launch warranty. Bug fixes, UI tweaks, and deployment support. No retainer.
  • All conversations are NDA-protected.

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