Using the 'TextToSpeech' API allows developers to give their apps a voice of their own. You are able to pass text to the app (such as user generated input), and the app will be able to read this out to the user which is especially useful for the visually impaired, or some sort of app which requires information to be read out.
The API allows you to select from which ever voices are available on the device, and you can also change the volume and pitch of the voice used. Most importantly, you are able to set up an event listener that can detect the status of the speech, so if there was an instance that the API failed, your app could react accordingly by trying again or displaying an alert on the device screen.
Fore more information on the API and the available functionality, see here:
Keywords: Text to Speech, API, Lollipop