What is the Speech To Text application, how does it work?

According to the introduction of Xenom Apps, Speech To Text is a Tools app on the Android platform. There is currently a 5.4.1 version released on Mar 22, 2019, you can see the details below.

A simple to use app for dictating text which can be sent as an SMS or Email or copied and pasted into another app. The app uses Androids built-in Speech Recogniser to turn speech into text. The app is also capable of speaking text out using your built-in TTS Engine.

A new innovative sliding tab design makes it even easier to use the app.

You are able to send dictations to contacts from your phonebook (permission required).

What's new in version 5.4.1 * Instant dictations!
* Offline Support
* Customise font size
* Auto save changes to open note when exiting app
* Show warning when about to discard unsaved changes
* Support more TTS languages
* Revamp Settings UI
* Improve theming for newer versions of Android
* Fix repeated dictations bug
* Fix settings activity back button bug
* Lots of small bugfixes (including sharing TTS audio bug)