Speech Assistant uses iOS voices. Some voices will need to be downloaded before use:

To download a voice:

1. Go to iPad Settings, then tap, Accessibility.
2. Tap Read and Speak, then tap Voices.
3. Select the cloud icon next to the desired voice to download it.

To change the voice in the app:

1. Select the Settings icon (wheel icon) in the action button area (top right corner of the screen).
2. Select Speech, Recordings, and Sound then Select Voice.

Select a voice — a blue checkmark will appear next to the selected voice.