Android provides many accessibility features such as [Talkback], [Text and display] ([Font size], [Color correction]), [Extra dim], [Dark theme], [Magnification], and more.
You can find accessibility features under [Settings] > [Accessibility].
Visit Google Accessibility Help at support.google.com/accessibility/android for more information.
Real-time Text (RTT) is a text service that carriers provide in certain countries/regions. It allows each character in a message to be read as it is typed. Check with your carrier to learn whether RTT is available with your service plan. Please note that in order to contact 911 using RTT in the United States, your phone may need to have a SIM card installed. For more information about using RTT on your phone, please visit support.google.com/accessibility/android.