"It's been difficult trying to communicate with him," said Ebon Mayor Ione deBrum.
"I've gotten to know him through pictures he's drawing. He said he was on his way to El Salvador by boat when it started drifting."
The remaining details remain sketchy, particularly regarding the fate of a companion, whom Ivan said died several months ago.
Vaca said Ivan was disorientated and did not know what had happened during his long stint at sea.
"He feels a little desperate and he wants to get back to Mexico, but he doesn't know how," she said.
Ivan appears to have survived by eating turtles, birds and fish and by drinking turtle blood when there was no rain.
He caught the animals with his bare hands as there was no fishing gear on board the boat. There was a turtle on the boat when it landed at Ebon.
"We've been feeding him nutritious island food and he's getting better," deBrum said. "He has pain in both knees so he cannot stand up by himself. Otherwise, he's OK."
Ivan is expected to arrive in Majuro late Monday morning.
His talk with Vaca, which took place via radio, is believed to be the first time in many months that the Mexican has had a conversation that he was able to understand.
- UK Independent