Voice messages from Telegram Premium users are sent to Google to convert their content into text, Habr author under the nickname snaker4 noticed.

Snaker4 noticed that clause 7.4 of the user agreement states that voice messages are sent to "Google LLC, a subsidiary of Alphabet Inc." According to the clause's description, Telegram uses "third-party" technology to transcribe audio messages.

"This technology is still evolving and there is no guarantee that every voice message you try to convert to text will be correctly transcribed or decrypted at all. The accuracy and availability of this technology is dependent on a third party (Google LLC, a subsidiary of Alphabet Inc.) and we cannot guarantee that it will always be so," reads the user agreement.

Not all users took this unequivocally. For example, the author of the Telegram channel "Backdoor" wrote in a post dedicated to this feature of the messenger that it creates a hypothetical possibility of Google listening to audio messages.

At the same time, he notes that the decryption function is not available in secret chats. Probably just for the reason of avoiding the potential disclosure of their content by a third party.