For versions below 6.6

You can change the speed of audio as per the child's needs. 

Tap Settings > Speed (under Audio settings) to change the Speed to ‘slow’.

For versions 6.6

Here's a step-by-step guide:

  1. Open the Avaz app.
  2. Navigate to Menu at the top right.
  3. Select "Settings"
  4. Choose "Voice"
  5. Pick the language you've selected.
  6. Under "Configuration", you will find options for "Voice Speed" and "Voice Pitch."

You can customize the speed and pitch to your liking.