Elsi Edwards loves playing with her siblings and chatting with family and friends.
But the five year old, from Bridgend, has a severe anxiety disorder called selective mutism - meaning she cannot talk to anyone else.
Now her family wants to raise awareness of the anxiety disorder to help others.
Her mother Hannah, said: "She's unable to communicate with any adults outside the family home and that can include family members."
She added: "She hasn't been able to communicate as yet in school, she's unable to read to her teachers, she's unable to ask to go to the toilet or ask if she needs anything.
"So it does have quite a large impact on her everyday life."
The condition affects about one in 140 children and is more common in girls and in families who speak more than one language - Elsi's family speak Welsh and English.
"Elsi cannot speak in certain situations," Hannah, a photographer, said.
"There's no choice in the matter at all. The only way speech will come is if the anxiety levels are lowered to a point where she's completely comfortable.
"We knew it was more than shyness and that it was something we needed support for."
The family said they were lucky they were listened to when they first had concerns.
They had help from a health visitor and speech therapist and Elsi's school, Ysgol Iolo Morganwg, adapted to her needs.
Speech therapist Lowri Roberts, who worked with the family, said: "It's very important to make the child feel at ease, to let them know they don't have to speak until they're ready.
"You shouldn't ask them questions or put pressure on them to talk."
Elsi's dad, Dafydd, said it was important to get help early: "The condition can stay with you.
"We are trying to work as early as possible with Elsi so that she doesn't have this condition into her teens and into adulthood.
"She's happy and funny. It's such a shame other people can't see her personality."
Hannah has challenged herself to run 100 miles by the end of the month to raise awareness of selective mutism.
She has been posting updates on social media.
"Since I've been doing the challenge we've had so many messages from doctors, teachers, parents who've never heard of selective mutism," she said.
"I was a teacher for 10 years and never once came across the term. I think there probably are a lot of people out there who aren't having the right support and it's purely because of a lack of understanding."
By talking about selective mutism she hopes to make life easier for others with the condition.
"We're so proud of Elsi, who goes out bravely every day without complaining," she said.