At four years old, she had never been able to say Mummy or Daddy.
Nor could Rose Willcocks tell her parents if she was hungry, tired or unwell after being left all but mute by an extremely unusual genetic condition.
But to her parents' astonishment, Rose has suddenly revealed she has a great deal to say for herself - but only to animals.
She began talking to cows during a stay at a farm which was part of her therapy. Her parents now say she turns into a chatterbox as soon as she is in the company of animals.
The discovery has given them hope of improving Rose's condition.
Her mother, Esme, 37, who has nicknamed her daughter Miss Dolittle after the fictional doctor who could talk to animals, said: "She began to vocalise with the cows. We had never heard Rose vocalise before and we were overjoyed."
Her mother, Esme, 37, who has nicknamed her daughter Miss Dolittle after the fictional doctor who could talk to animals, said: "She began to vocalise with the cows. We had never heard Rose vocalise before and we were overjoyed."
Rose has a chromosome defect which has left her with a floppy voicebox and windpipe. She also has learning difficulties and autism.
Mrs Willcocks and husband Dave, 41, an IT administrator have another daughter, Ruby, two.
The family, from Bishop's Stortford in Hertfordshire, arranged a therapy placement for Rose and stayed at a farm.
"We went to see the cows," Mrs Willcocks said. "Suddenly, Rose perked up. I did a double-take as I struggled to take in what I was hearing. She wasn't actually saying words but there were no two ways about it - she was talking to a cow."
"There was something about animals that made Rosie connect. We could barely get her to make eye contact or moan or groan but here she was, chatting like an old friend to the cows and horses."
"Her affinity with animals amazes everyone. She changes from an introvert into a chatterbox." The family are planning to take Rose to the U.S. for therapy, involving swimming with dolphins, in the hope she will continue improving.
Her mother said: "If we can move her on just a fraction further then it will have all been worthwhile."