To specify text-to-speech settings for your device, go to Settings and then Accessibility and then Text-to-speech output.

The following settings are available:

Preferred engine: The default text-to-speech engine choices vary by device. Options can include Google’s Text-to-speech engine, the device manufacturer’s engine, and any third-party text-to-speech engines that you’ve downloaded from the Google Play Store.
Engine settings: To change the settings for your selected text-to-speech engine, select Settings next to the name of your preferred engine.
Speech rate: Select the speed at which text is spoken.
Pitch: Make the speech pitch higher or lower.
Reset speech rate and Reset speech pitch: If you adjust the speech rate or pitch, use these controls to reset to the original rate.
Listen to an example: Select this option to hear a short demonstration of speech synthesis.
Default language status: Here your device displays the current status of your default language (such as “fully supported”). The default language is the language selected in your preferred Text-to-speech engine.