Digitalent - Speech To Text (STT) / Text To Speech (TTS)
In order to explain how STT ans TTS work we'll be using the Web Speech API.
The Web Speech API has two parts: SpeechRecognition (Speech-to-Text - STT) and SpeechSynthesis (Text-to-Speech - TTS).
Also check mozilla documentation to learn more about it.
Not all browser support Web Speech API thus it's recommend the use of Google Chrome.