Privacy Policy

1. Information we collect

Information you provide

• Account information — your name and email address when you sign in (via Google OAuth or email), plus any profile details you add (interests, occupation, goals, target language, native language).
• Onboarding responses — your self-assessed level, goals, learning style, and time commitment.
• Payment information — handled by Stripe. We do not store full card details on our servers; we receive a customer ID and subscription status from Stripe.
• Support communications — anything you send us by email or other channels.

Information generated by your use of the Service

• Voice recordings and transcripts — audio captured during voice lessons, real-time speech-to-text transcripts, and the tutor’s responses.
• Lesson data — the lesson plan, errors flagged during the session, corrections, vocabulary you produced, and your progress over time (your “learner model”, including CEFR scores and skill mastery).
• Memories — facts the tutor extracts from your conversations (for example: “learner is preparing for a trip to Tokyo”) to personalize future sessions. You can request these be deleted at any time.
• Usage data — session duration, features used, device and browser information, IP address, and approximate location.

Cookies and similar technologies

We use cookies and local storage for authentication, session management, and analytics. You can disable cookies in your browser, but parts of the Service may not work without them.

2. How we use your information

• Operate the Service — generate lesson plans, transcribe and respond to your speech, track your progress.
• Personalize your learning experience based on your level, errors, and stated goals.
• Process payments and manage your subscription.
• Send transactional emails (account, billing) and, with your consent, occasional product updates.
• Improve the Service — analyze aggregated usage patterns and debug issues. We do not use your voice recordings to train third-party foundation models.
• Detect, prevent, and respond to abuse, fraud, and security issues.
• Comply with legal obligations.

3. How we share your information

We do not sell your personal data. We share information only with the service providers we need to operate the Service:

• Supabase — authentication and database hosting.
• Anthropic — Claude models that power the tutor’s reasoning and responses. Your conversation text is sent to Anthropic to generate replies.
• LiveKit — real-time audio infrastructure for voice sessions.
• Soniox and Deepgram — speech-to-text providers that transcribe your audio.
• Cartesia and Rime — text-to-speech providers that synthesize the tutor’s voice.
• Stripe — payment processing and subscription management.
• Resend — transactional email delivery.
• Google — OAuth sign-in.
• PostHog — product analytics.
• Vercel — application hosting.

Each provider only receives the data necessary to do its job and is contractually required to protect it. We may also disclose information if required by law, to enforce our Terms, or to protect the rights, property, or safety of users and the public.

4. Data retention

We keep your account data, lesson history, learner model, and memories for as long as your account is active. If you delete your account, we delete the associated personal data within 30 days, except where we are required to retain it for legal or financial reasons (for example, tax records related to payments).

Audio recordings of voice sessions are not retained by default after the session ends — only the transcript and structured lesson data are kept.

5. Your rights

Depending on where you live, you may have the right to access, correct, export, or delete the personal data we hold about you, and to object to or restrict certain processing. To exercise any of these rights, email us at andrew@lingle.ai. We will respond within a reasonable time and free of charge.

California residents have additional rights under the CCPA/CPRA, including the right to know what personal information we collect and to request its deletion. We do not sell personal information.

6. Security

We use industry-standard security measures — encryption in transit (HTTPS, WSS), encryption at rest for our databases, and access controls on internal systems. No method of transmission or storage is perfectly secure, but we work to protect your data.

7. Children

The Service is not directed to children under 13, and we do not knowingly collect personal information from children under 13. If you believe a child has provided us with personal information, please contact us and we will delete it.

8. International users

Lingle is operated from the United States. If you access the Service from outside the US, your information will be transferred to and processed in the US (and other countries where our service providers operate), which may have different data protection laws than your country.

9. Changes to this policy

We may update this Policy from time to time. If we make material changes, we will notify you by email or via a notice in the Service. The “Last updated” date at the top reflects the most recent version.

10. Contact