Gmail, the world's most popular email service, is testing a new built-in functionality that allows users to draft emails using voice. The feature can be activated by triggering a flag, and when users start writing or replying to an email, a new button named 'Draft email with voice' appears with a big mic button. Users can start recording by tapping on it, stop it by pressing the same button, and then tap the 'Create' button. Gmail will write the draft using AI, allowing users to edit the draft to their preferences before sending the email. This feature is similar to Google Keyboard's existing speak-to-type functionality but uses generative AI and is natively integrated with Gmail, making it more accessible to more users. Google added strings related to the feature in October last year, but it is unclear when the new functionality will be available to everyone.