If you want your texts, messages or notes to be read out loud on your iPhone or other iOS device, go to Settings, General and then tap Accessibility and turn Speaker Selection to ON. You can then choose what voice you want to use to have your texts, messages or notes read in including all types of different accents.
You can also choose how fast or slow you want the voice to read your texts, messages or notes on your iPhone or other iOS device by sliding the Speaking Rate button to your desired speed. If you want the words highlighted as they are read, go to Highlight Words and turn to ON. You can turn the speaker selection on or off at any time and adjust the settings as often as you like.