A woman believed by some to have lived in the jungle for 19 years has tried to speak, says a Spanish psychologist who visited her in north-east Cambodia.
The woman does not speak in any identifiable language
Hector Rifa, of Psychologists without Borders said the woman "made some words" and smiled in response to a game involving toy animals and a mirror.
However, she does not speak in any recognisable language, Mr Rifa added.
She was reportedly discovered 10 days ago, naked and scavenging for food in the forests of Rattanakiri province.
A family claims she is their daughter, Rochom P'ngieng, who went missing when she was eight.
They say they identified her from a scar on her arm.
But others are sceptical, saying she could be somebody with mental problems, or have gone missing more recently.
"This is not something magical... I think many of the people who come here will be disappointed - she is a normal woman, a little shy," Mr Rifa told AFP news agency.
"We did some tests and she showed some response, she made some words - even to me and I am not part of the family," he added.
The woman has tried to run away from the family she is living with
"This is only small, small, small, but it means that she can do it," he said, explaining:
"She verbalises, but the sounds, even the family does not understand."
Mr Rifa, of Spain's Oviedo University, has been working with Cambodia's hill tribes on issues of health promotion for the last four years.
He said it was too early to assess the woman's mental state and that she needed time to adapt to her environment.
"She needs assimilation - she needs to see objects and to hear sounds," he said.
Meanwhile, village policeman Sal Lou who claims to be the woman's father, said his daughter smiled for the psychologist.
"She seems not to fear anymore", he said, "but the only thing is that every night she sleeps only a short time."
He has said he will have DNA tests taken to prove she is the daughter he lost when she disappeared while tending buffalo in 1988.
The woman is reported to have tried to run away several times as locals and journalists have descended on the village to look at her.
Sal Lou described how she was naked and "walking in a bending-forward position like a monkey" when he first saw her. "She was shaking and picking up grains of rice from the ground to eat," he added.
However, some are beginning to doubt his story.