This youtube showed how the researches try to observe elephant by listening to their sound and related it to their behaviur .fires,they mentioned how distinguish boy and girl of elephant .then,how they communicate by their sound  and they tried to put word together to understand .finally, they said sound of elphant doesn't mean that elephant talks.

  I like this clip ,it is amaizing to learn how animal communicate with each other .I recommend it to people how love science and nature like me .I loved the researchers who spend alto of time to transfer this researches for us.