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Vollio Privacy Policy

Last Updated: October 8, 2026

Welcome to Vollio (formerly "Lingo Diary"; the "Service" or the "App"). This Service is provided by SPARKLECT CO., LTD. ("we", "us", or "our"). We take your privacy seriously. This Privacy Policy explains how we collect, use, disclose, and protect your information.

The App helps users practice their target language in context through AI role-play conversations, and also offers supporting features such as a language diary. By downloading or using the App, you agree to the practices described in this Privacy Policy.

1. Information We Collect

To provide AI role-play, conversation assistance, diary generation, and personalized language learning services, we may collect the following categories of information:

1.1 Information you provide

  • Account information: When you sign in with a third-party account (such as Apple or Google), we collect the account identifier provided by that service, along with the email address and name you agree to share (or, if you choose to hide your email, the relay address provided by that service), to create your account and sync data.
  • Learning settings: Your target languages, native language, and proficiency level for each language.
  • User content (text): Your conversation messages with the AI and your diary entries.
  • Role-play scenario settings: The location, your role, and the other character's role you enter when creating a scenario, and the scenarios, stages, and goals generated from them. If you use scenario sharing, this also includes the scenarios you choose to share and their sharing settings.
  • User content (voice): If you use the voice message feature, the audio you record (AAC m4a format, up to 30 seconds per message) will be uploaded to Firebase Cloud Storage and sent to Google Gemini for speech transcription and pronunciation teaching analysis.
  • Subscription records: Your subscription status and the transaction receipt information returned by the app store.

1.2 Information collected automatically

  • Device information: Including device model, operating system version, IP address, language settings, time zone, and the IDFV (Identifier for Vendors) — Apple's "same-vendor device identifier" used to recognize the same device across apps published by us, supporting account linkage and analytics.
  • Learning activity records: Your learning activity in the Service, such as the number of messages sent, listening and speaking time, audio playback, stage and goal completion, badges, and your usage of each AI feature.
  • Usage data and analytics events: Through tools such as Firebase Analytics, we record how you interact with the App. This includes but is not limited to: features clicked, pages viewed, time spent, feature usage frequency, and crash reports.
  • No cross-app tracking: The App does not access your Identifier for Advertisers (IDFA) and does not track your activity across other companies' apps or websites for advertising purposes.

2. How We Use Your Information

We use collected information for the following purposes:

  • Core service delivery: Sending your text conversations, voice recordings, scenario settings, and learning settings to third-party generative AI models to generate role-play scenarios and stages, AI character replies, goal evaluations, rephrasing suggestions, voice transcripts, pronunciation teaching, AI character voices, and diary content.
  • Account management and sync: Using Firebase services to store your conversation records, diaries, role-play scenarios and practice progress, voice recordings, and settings in the cloud, ensuring data synchronization across your devices.
  • Learning progress: Calculating and showing you your message counts, listening and speaking time, stage progress, badges, and other learning results.
  • Scenario sharing: After you choose to share a scenario, showing that scenario to other users.
  • Content safety and abuse prevention: Detecting and handling content that violates the Terms of Service, processing reports, and monitoring abnormal usage patterns to operate dynamic risk-control mechanisms that prevent abuse.
  • Analytics and product optimization: Analyzing usage behavior and learning activity records. This helps us understand which features are most popular, identify usability bottlenecks, and improve the user interface, AI generation quality, and service performance.
  • Subscription management: Verifying transaction receipts and managing your subscription status.

3. Information Sharing and Third-Party Services

We do not sell your personal information to third parties. However, to operate the App, we share specific data with the following service providers:

3.1 AI technology providers

To provide role-play, personalized language learning guidance, diary generation, and voice teaching services, the App integrates third-party artificial intelligence models.

  • Recipients: Relevant data is sent to Google Gemini.
  • Data sent: Limited to the text conversations, voice recordings, scenario settings, target language, native language settings, and language proficiency level needed to provide the Service. AI character voices are generated by sending the AI's reply text to Google Gemini.
  • Privacy commitment: We do not proactively send your name, email, phone number, precise device location, or any personally identifying information to AI providers.
  • Data security and compliance:
    • No-training policy: Per the provider's current API terms of service, data sent via the API is not used by default to train their foundational AI models.
    • Secure transmission: Our selected provider offers industry-standard encryption and security protections for API transmissions.
    • Temporary storage and deletion: Data is only temporarily stored on the provider's protected servers for safety review purposes (e.g., abuse prevention), with retention periods governed by their internal policies.

3.2 Cloud storage and infrastructure

  • Google Firebase: We use Firebase for authentication, database and file storage (including your voice recordings and AI-generated audio), and data synchronization. Your data is securely stored on Firebase servers.
  • Google Cloud BigQuery: We export learning activity records (such as activity type, time, language, stage, and feature usage) to BigQuery for internal statistical analysis. Exported data is linked by account identifier and does not include your conversation content, voice recordings, diaries, or scenario text.

3.3 Analytics services

  • Firebase Analytics and Firebase Crashlytics: We use these tools to collect usage behavior data and crash reports. Google may use the collected data to analyze App usage patterns.

3.4 Sign-in services

  • Third-party sign-in services such as Apple and Google: When you sign in with a third-party account, that service processes your sign-in data under its own privacy policy and provides us with the verification result and the account information you agree to share.

3.5 Other users

  • Only the role-play scenarios you choose to share are visible to other users. Your conversation records, voice recordings, diaries, practice progress, and account information are not made public by sharing a scenario.
  • Depending on the design of the sharing feature, a shared scenario may also display the public name you have set.

3.6 Legal disclosure

We may disclose information when required by law, court order, or a lawful request from a competent authority, or when necessary to protect the rights and safety of the Service, our users, or the public.

4. Subscriptions and Payments

The Service is currently in a free beta, and you will not be charged anything during the beta. Once paid subscription plans launch, all transactions will be processed through the App Store or Google Play payment systems. We do not collect or store your credit card or bank account information. We only receive transaction receipts returned by the app stores to verify your subscription status.

5. Data Security and Retention

  • Security: We use industry-standard encryption technologies (such as SSL/TLS) to protect your data during transmission and storage.
  • Data retention: We retain your data while your account remains active. If you choose to delete your account, we will permanently delete your personal information and related data (conversation records, diaries, role-play scenarios and practice records, voice recordings, settings, etc.) from our servers within a reasonable period.
  • Shared content: After you delete a shared scenario or delete your account, the scenario will no longer be public. Other users who have already added the scenario may retain their own practice records.
  • Statistical data: De-identified or aggregated statistics that can no longer identify you may be retained after account deletion for analysis and service improvement.

6. Your Rights

Depending on your region, you have the following rights:

  • Access and correction: You may view and edit your data at any time in the settings page.
  • Account deletion: You can find the "Delete Account" option in the account management page of the App. Once executed, all your data (including conversations, diaries, role-play scenarios and practice records, and voice recordings) will be permanently deleted and cannot be recovered.
  • Other requests: If you wish to access, obtain a copy of, correct, stop the processing of, or delete your personal data, please contact us using the details in Section 9.

7. Children's Privacy

The App is not designed for children under 13 years of age (or the age specified by local law). We do not knowingly collect personal information from children. If we discover that we have inadvertently collected information from a child, we will immediately delete such information.

8. Changes to This Privacy Policy

We may update this Privacy Policy from time to time. Any changes will be posted on this page with the "Last Updated" date revised accordingly. For significant changes, we may notify you through an in-app notification.

9. Contact Us

If you have any questions about this Privacy Policy or our data handling practices, please contact us through the following:

  • Company name: SPARKLECT CO., LTD.
  • Email: service@sparklect.com