Contact support
LingoUnion is operated by Hongyu Zhang, an individual developer.
For a LingoUnion question, email support@lingounion.com. Support is available in English only. Email support is not a real-time, telephone, or emergency service.
Published support hours are Monday through Friday, 9:00 a.m.–5:00 p.m. Pacific Time, excluding U.S. federal holidays. We aim to send a first response within two business days for purchase or subscription-entitlement questions, within three business days for general questions, and within 24 hours for urgent security reports. These are response targets, not guaranteed resolution times or a promise of 24/7 service.
LingoUnion version 1.0 is available now on the US App Store for compatible iPhones. Version 2.0 adds AI-generated learning in 20 target languages. View LingoUnion on the App Store.
Send information safely
Do not email learning sentences, target English sentences, transcripts, recordings, handwriting, learning history, passwords, verification codes, payment details, or signed transaction data.
For most issues, support needs only:
- the LingoUnion app version and build number;
- the iOS version and iPhone model;
- the App Store country or region;
- a fixed error code shown by the app;
- the approximate time of the issue;
- whether the iPhone was connected to the internet;
- a brief description that does not contain your practice sentence.
If a screenshot is necessary, use only a settings, compatibility, or subscription-status screen that does not show learning content.
System requirements
LingoUnion is for adults age 18 or older using a compatible iPhone in the United States. Version 2.0 offers 20 target languages and requires these capabilities:
Internet and AI
A network connection is required to authenticate the app, verify current subscription access, and generate each new translation and speech file through LingoUnion and OpenAI.
Speech recognition
The iPhone must be able to transcribe the selected target language for the current speaking attempt.
AI voice
Select one of the ten available AI voices. Marin is the default, and generated audio is saved with the new sentence.
Handwriting
You need an available iPhone handwriting keyboard for the selected target language to complete handwriting practice.
The 20 target languages are Arabic, Dutch, English (United States), French, German, Hindi, Indonesian, Italian, Japanese, Korean, Polish, Portuguese (Portugal), Russian, Simplified Chinese, Spanish, Thai, Traditional Chinese (Taiwan), Turkish, Ukrainian, and Vietnamese. Speaking or handwriting readiness can still depend on Apple permissions, installed keyboards, language resources, and device support.
Subscriptions and Apple billing
Subscriptions are purchased and managed through Apple. LingoUnion does not receive or control your Apple Account password, payment-card details, or two-factor authentication code.
Apple determines introductory-offer and refund eligibility. Support can explain how LingoUnion reads a verified entitlement, but cannot grant a separate free period or approve an Apple refund.
Learning records
Learning records remain only on the iPhone where they were created. LingoUnion does not provide cloud backup, sync, export, migration, reinstall recovery, or cross-device restoration.
Restoring purchases can restore an eligible Apple subscription entitlement, but it does not restore learning records. Support cannot retrieve a sentence or learning history because LingoUnion does not keep a developer-operated server copy.
Error codes and safe troubleshooting
If LingoUnion shows one of the fixed codes below, you may send the code to support together with the app version, iOS version, iPhone model, approximate time, and whether the iPhone was online. Do not send the sentence, transcript, recording, handwriting, screenshot of a learning screen, complete Apple transaction, or full device log.
Sentence input
INPUT_EMPTY, INPUT_TOO_SHORT, INPUT_TOO_LONG, INPUT_MULTILINE, INPUT_MULTIPLE_SENTENCES, or INPUT_NO_LETTER_OR_IDEOGRAPH means the current entry does not meet the one-short-complete-sentence rule. Edit the entry in the app; do not email the sentence to support.
Translation
TRANSLATION_PAIR_UNSUPPORTED, TRANSLATION_RESOURCE_PENDING, TRANSLATION_TIMEOUT, TRANSLATION_EMPTY_RESULT, TRANSLATION_CANCELLED, or TRANSLATION_SYSTEM_FAILURE concerns translation readiness or the current AI request. A fixed CONTENT_… or AUTH_… code concerns content generation, app authentication, subscription verification, or the content gateway. Check the network, keep the app open, and follow the exact in-app instruction. If the app says generation may already exist or asks you to contact support, do not repeatedly retry or clear data; send only the fixed code and content-free details listed above.
Speech and microphone
SPEECH_PERMISSION_DENIED, MICROPHONE_PERMISSION_DENIED, SPEECH_UNAVAILABLE, SPEECH_NO_RESULT, SPEECH_TIMEOUT, SPEECH_SYSTEM_FAILURE, or AUDIO_SESSION_FAILURE concerns speech recognition, microphone permission, or the current audio session. Review iPhone permissions, stop other audio activity if necessary, and retry without sending a recording.
Generated voice and playback
A fixed SPEECH_… content code concerns AI speech generation. TTS_EN_US_MISSING, TTS_SELECTED_VOICE_MISSING, TTS_PLAYBACK_INTERRUPTED, TTS_SYSTEM_FAILURE, or an audio-read code concerns voice availability or playback of an already generated file. Follow the exact in-app instruction and do not repeatedly request generation after a conflict or uncertain result.
Handwriting
HANDWRITING_CONFIRMATION_REQUIRED, HANDWRITING_EMPTY_RESULT, or HANDWRITING_SYSTEM_UNAVAILABLE concerns the English handwriting keyboard or its current result. Complete the in-app confirmation, check the iPhone keyboard configuration, and retry.
Compatibility or app state
CAPABILITY_CERTIFICATION_EXPIRED, SYSTEM_TEMPORARY_FAILURE, INVALID_STATE_TRANSITION, or DUPLICATE_ATTEMPT_CALLBACK means the compatibility result is stale, a system action failed temporarily, or the app rejected an unsafe duplicate/state transition. Return to the compatibility check and retry. If the code repeats, send only the fixed code and the content-free environment details listed above.
Frequently asked questions
Why can’t I start a new sentence?
LingoUnion allows at most one new sentence per day. A new sentence also waits until due reviews are complete, storage is healthy, required system capabilities are available, and a verified subscription entitlement permits learning.
Why is a language supported but not ready?
Your iPhone may report that a language pair is supported while still requiring an Apple language-resource download, permission, network access, or another system preparation step. Follow the in-app check, complete the suggested system action, and run the check again.
Does LingoUnion grade my pronunciation?
No. The app compares the text your iPhone transcribes with the visible target sentence. A match result is not a professional pronunciation score, grammar assessment, or general English-proficiency rating.
Can support recover a deleted sentence?
No. Deleted learning records cannot be recovered by support. LingoUnion does not keep a developer-operated server copy of the learning library and has no learning-data backup or export.
What does Restore Purchases restore?
It restores only an eligible Apple subscription entitlement. It does not restore sentences, progress, scores, review dates, or any other learning record.
Why don’t I see the one-month free trial?
Apple decides introductory-offer eligibility from the subscription group and prior offer use. If Apple reports that you are not eligible, LingoUnion shows the current annual subscription without claiming or creating a separate local free period.
Is one App Store month always 30 days?
No. A one-month trial follows Apple’s calendar-month rules and may span 28, 29, 30, or 31 days. Review the dates and final terms shown by Apple before confirming.
What happens if I cancel automatic renewal?
Canceling through your Apple Account prevents a future renewal but does not end access before the current verified subscription period expires. Deleting the app or learning records does not cancel the Apple subscription.
Why is learning paused while my subscription is active?
A verified subscription permits access, but learning also requires the content service, network, speech recognition, handwriting, storage, and time state to be available. Subscription management, support, privacy information, and learning-data deletion remain available while learning is paused.
What happens if a required language capability stops working?
Learning pauses and completed progress remains on the iPhone. You can check the missing capability, retry, manage the subscription, read privacy and support information, and delete learning data. LingoUnion does not silently switch providers or send an AI request without consent.
Can I use LingoUnion for legal, medical, or emergency translation?
No. LingoUnion is only for short, everyday beginner language practice. Do not rely on it for medical, legal, financial, emergency, professional, safety-critical, or other high-stakes communication.