When I was 15 years old, I stopped speaking. Nineteen years later, I'm still not exactly sure why – I think I felt that words got me into trouble, made me vulnerable to the judgment of others. The boys in my class were always teasing me, telling me to shut up and calling me a prat. As a young teenager, I was devastated that my attempts to fit in were spurned. I tried to play the class clown, but I still didn't feel accepted: I was always the third friend in a group, never the first or second. One day, I remember collapsing into uncontrollable sobs behind the sports hall.

So throughout my teens and early 20s, a time when most young people learn to express themselves, I clammed up – dealing with the wider world only in whispers and shrugs. My isolation led to indescribable loneliness and to cycles of guilt and pain that nothing could relieve. It was both self-imposed and yet almost dictated by my body, as it seemed the only way I could ever feel "normal".

Despite early promise, my childhood development had stopped when I began at playschool around the age of four. My parents realised I was different from other children and from my sister, who was two years younger. I couldn't mix or socialise. I was naive. I took conversations very literally. I still do.

Learning was impossible and my father felt I was being lazy. I was also desperately shy. An educational psychologist marked me down as "below average intelligence" and I was written off. Then, at 14, a second psychologist saw potential in me – she said I was intelligent but insecure, and needed to change schools for a fresh start.

My parents sent me to a different comprehensive. I knew no one and I had the chance to reinvent myself. Cheered by the psychologist's faith in me, I worked hard and became a swot. My parents were proud.

But I quickly began to associate being quiet with being accepted. If I really did have to communicate, I would whisper softly, use a nod or a shake of the head. Or I would hide my mouth with my hand to stop any words coming out.

Occasionally, I did let myself go and be silly. But the guilt afterwards was terrible. I didn't want to go back to being loud – and being rejected for it. Instead, I saw myself as some sort of tragic Morrissey-Romantic poet figure compared with my classmates. I later learned I was famous as "the kid who never spoke".

After getting a couple of GCSEs (unthinkable just two years before), I went into the sixth form. Although I didn't know anyone there, I was known as the "sweet, shy boy who never spoke". That felt good.

But I was also frustrated. After I left school in 1994, my isolation intensified and I'd communicate in the barest of whispers. Finally, when I was 20, I was referred to a psychiatrist and he diagnosed me with Asperger's syndrome, a mild form of autism. It was such a relief to know what was happening that I cried on the bus on the way home.

It took a further five years to speak again, a decision that was as much a surprise to me as it was to everyone else. I had become trapped; I worried that I was being silent to get attention. This made me feel horribly guilty, which made me even more fearful and introverted. But I knew I had to confront my fears if I was to have a normal life – something I craved.

One morning, I decided I wanted to speak. I began with "Hello". That was all. Gradually, I built up my speech and learned to cope with the accompanying guilt. I still feel terrible if people say I'm too chatty or have talked for too long. Perhaps they think I am – that dreaded childhood insult – a prat.

However, I've pushed myself hard, becoming more confident. I've always loved books, but now I revel in spoken language, too, and I've enrolled on a course studying English and creative writing.

In the end, I found talking a massive relief and I definitely get more than usual pleasure from the use of language. It's still such a novelty for me discovering different words – ones that can sound so complex, and carry so much emotion.

I feel like crying when I think of what I have missed out on, but I don't bottle it up any more. Instead, I enjoy talking about it.

• As told to Victoria Lambert.

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