From the sender to your screen
For an encrypted chat, the sender’s device encrypts the message for delivery. Your phone receives it and decrypts it. If the message needs translation and cloud translation is enabled, the readable text goes to AiThao’s translation service. The result returns to your phone for display.
Encrypted delivery and cloud translation are separate steps. The cloud needs readable content for the second step; that processing is not end-to-end encrypted between the two phones. Translation is not performed entirely on your device.
Which language you read
Text translation supports 96 languages. Settings → Translation separates Messages, Voice in calls and Groups. Choose the language you want to read for messages; it need not match the language you want to hear on calls. In a multilingual group, each reader gets their own translation instead of everyone being forced to read one shared language.
When the source already matches your reading language, there may be nothing to translate. An untranslated message can also mean translation is disabled or a result has not arrived. Do not treat the absence of translated text as proof of an encryption failure.
Translation on the front, original on the back
A received translated message normally shows the translation. Double-tap its card to see the original, then double-tap again to return. It is one card with two faces. A single tap remains available for links and other actions in the message.
On your own message, the reverse side can show how it reads in the other person’s language. That is a translation preview, not a read receipt or proof of the exact wording they saw. The message-translation feature page explains the gesture and the 3D hint.
Automatic and requested translation
Cloud translation is on by default and can be switched off in Settings → Translation. This stops automatic cloud translation; it does not erase results already received or undo processing that already happened.
On iPhone, double-tapping a received message that has no translation can request one when Cloud translation is enabled. That is different from turning over an already translated message. When Cloud translation is off, the translation request does not send the text to the service.
Voice messages and groups
Voice translation adds speech recognition and spoken output: the listener’s phone asks for a recording to be transcribed, translated and spoken in the chosen language. The original recording and the translated result are different things; a synthetic rendering is not the original audio.
Group message translation is also per reader. End-to-end encryption protects the group’s message content in delivery; the server still holds group metadata. A member’s cloud translation request has the same readable-content boundary as in a one-to-one chat.
Checking a translation
Use the original when wording matters, and ask the sender to confirm a name, address or amount. Automatic translation can lose tone or misread an abbreviation. If the two versions seem inconsistent, the original is a reference for a follow-up question, not a guarantee that either person has understood the message.
AiThao’s translation service returns the result without storing it on the server. This is not a claim that cloud providers never process or retain data under their own terms. The translation-security page and privacy policy explain the handling boundary.