A woman who was taunted as a child because she couldn't speak said she forgives the children that bullied her at school.
Niamh Foy, 19, was diagnosed with selective mutism at Alder Hey when she was three years old.
Selective mutism is a rare type of anxiety caused by problems with the amygdala in the brain.
Alder Hey said people with the condition have an overactive amygdala when they are stressed, causing their speech ability to shut down leaving them unable to speak.
The condition causes the sufferer to become effectively mute in environments such as school, going to the shops or playing sports.
Niamh said: "As a result of this I was a lonely child, I spent a lot of my youth in hospital and at specialist clinics.
"I used to play on my own at school - when I was in school - and was bullied sometimes by other children.
"I forgive them for this because they didn’t understand what was wrong with me but I still felt sad watching the other children play without me.
"That’s the most upsetting thing about the condition - you can understand language perfectly, you just can’t reply.
"Your voice, and your identity, is stolen from you."
But it wasn't just children that reacted cruelly to Niamh's condition.
In an interview with the BBC, Niamh said as she struggled to talk, adults would ask if she was being rude or put her silence down to bad behaviour or a lack of intelligence.
She said: "I remember being asked 'are you stupid?' by a lot by people in shops or at the park, because I couldn't reply to them when they spoke to me."
Years of speech therapy at Alder Hey, Niamh said, changed her life and put her on the path to recovery.
She added: "My therapist made me a paper lion that I could take to school with me to show how brave I was. I still have that lion at home in a box and it is a treasured possession.
"They worked with my school to ensure that I was treated equally and my classmates became a lot more accepting after they were taught what Selective Mutism was."
As a teenager, Niamh wanted to give something back to Alder Hey and joined a team of volunteers made up of young people who have used the hospital's services in the past.
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Since then she has visited universities to talk to doctorate-level clinical psychology students about their work and develop apps for young people struggling with their mental health.
Niamh said: "Being in a Youth Participation Group really opened my eyes as to how rewarding it was to give back to the community.
"For this reason, I decided to become a speech and language therapist myself, to help others like I had been helped."

Over lockdown, she has also set up her own online page, 'Niamh's Live-Streams' where she streams live a couple of times a week to give company to others who might be living alone or struggling with their mental health.
She added: "I still struggle sometimes with anxiety and low self-esteem, and I have a long way to go in my development as a person, but I wake up every day thankful for the opportunity to live and have a voice. Thank you so much Alder Hey, you truly are amazing.”