Recently, you may have noticed that the Google app received an updated, slightly clearer text-to-speech (TTS) voice. The more natural-sounding voice is a welcome change, but have you ever wondered how Google brings the words coming from your phone to life?

In the latest episode of Nat and Lo, a YouTube series where the two Google employees give you behind-the-scenes looks at what goes on at Google HQ, the hosts explore how the latest TTS voice update came to be. In the video above, you can check out part of the arduous process of recording thousands of lines, along with a little history of TTS.