'Speech is a right and not a privilege'
Media playback is unsupported on your device
Video

'Speech is a right and not a privilege'

Dr Vishal Rao has created a simple device to help throat cancer patients in India to speak again. Replacement prosthetic voice boxes can cost up to $1,000 (£750) but his Aum box costs just $1.

Go to next video: Keeping out the rain in India's slums