An orangutan has learnt to speak to humans.

Talking orangutan

Talking orangutan

The eight-year-old animal called Rocky has picked up language from people and has begun to churn out grammatically correct sentences with the new vocabulary he has acquired after a study took places at Indianapolis Zoo in America, according to Scientific Records.

Researchers were shocked by the primate's behaviour after he mimicked the tone and alternation, and discovered he can control the way he speaks, like people.

And it is believed Rocky could be the clue to understanding how language has evolved.

A researcher from the University of Durham, Dr Adriano Lameria, said: ''Instead of learning new sounds, it has been presumed that sounds made by great apes are driven by arousal over which they have no control, but our research proves that orangutans have the potential capacity to control the action of their voices.

''This indicates that the voice control shown by humans could derive from an evolutionary ancestor with similar voice control capacities as those found in orangutans and in all great apes more generally.''