Sitting together on the classroom floor in Kalyanpur in northwest India, a dozen children aged five and six are trying to identify Hindi words beginning with the "p" sound.

After a spontaneous "papa", the children unanimously agree on "papaya" — spelled out at the top of their lungs by the entire class.

But for these children, born into an Indigenous tribe in Rajasthan state, learning to read in a language neither they nor their parents speak is a challenge.