Painstakingly picked out on a cardboard alphabet grid by its severely autistic author, the acclaimed Japanese memoir The Reason I Jump, which provides a "revelatory" window onto life as an autistic teenager, is being translated into English by the award-winning author of Cloud Atlas, David Mitchell.

Mitchell's wife Keiko Yoshida spotted the 2006 memoir online. In the book the teenage author Naoki Higashida answers questions such as why he doesn't make eye contact when talking, why he can't have a proper conversation and how much he hates being talked down to. Yoshida thought it might be helpful, as the couple's own son is also autistic. Initially translating it just for their son's carers and for friends, Mitchell and Yoshida soon began to realise that the memoir might help a much wider audience.

"I could see how helpful it was for her in terms of understanding the autism in our own domestic situation," said Mitchell. "She did the heavy lifting from the Japanese into English, and in a sense I provided the stylistic icing on the cake. But I also needed to respect the fact that it was a 13-year-old boy writing, not a 44-year-old novelist, so it couldn't sound as if it was written for the New Yorker."

The memoir is the author's attempt to provide an insight into the world of autism, addressing topics such as beauty, time, noise and how he feels about the people around him. It also includes short stories. Mitchell compared it to The Diving Bell and the Butterfly, Jean-Dominique Bauby's bestselling account of life with locked-in syndrome which he dictated by blinking out the letters and the words with his eyelid.

Naoki Higashida

Higashida, said Mitchell, tapped out the memoir letter by letter on an alphabet grid on a piece of cardboard. "He points to each letter with his finger, and someone at his side collects the words and the sentences and the paragraphs. He's 13, and he's more of a writer than I am," said Mitchell, one of Granta's Best of Young British Novelists, who has been shortlisted for the Booker prize. "He can use a keyboard directly, but feels the cardboard has fewer distractions, and focuses him better."

As well as translating the book with Yoshida, Mitchell has also written an introduction, in which he calls the book a "revelatory godsend". "Composed by a writer still with one foot in childhood, and whose autism was at least as challenging and life-defining as our son's … reading it felt as if, for the first time, our own son was talking to us about what was happening inside his head," he writes.

"This book really does prove that there is so much going on beneath the sometimes very challenging surface of autism, of this small person you are in charge of with autism," he told the Guardian. "What this book does is make it undeniable that even in what appears to be a profoundly autistic person, there is someone as intelligent, as perceptive, as witty, even as language-loving, as you or me, and oh, that just makes the world of difference. I'm aware of not wanting to sound evangelical, but it really helped me turn a corner. If I have any influence in the public narrative about autism, I'd like it to be this."

Carole Welch, Mitchell's publisher at Sceptre – which will publish The Reason I Jump in July – said the memoir gives an "extraordinary insight into what it's like to have autism, and particularly as a child. David makes the point that there are accounts from adults with autism, but to get an insight into a child or teenager's point of view with autism is a revelation, really."

Welch described The Reason I Jump as "an important book", and said that Mitchell and his wife "hope it will be useful to people in the way it has been for them – for people who are caring for a child or a sibling with autism, but also that it can help change attitudes more generally. The assumptions we make about people with autism not having any empathy or imagination – well, Naoki makes it very clear that is not the case."

"I hope it finds as wide a readership as possible … I would love it to outsell anything I'd written, I'd love that," said Mitchell. "There's autism in the domestic sphere, which you can modify your environment around, and then there's the visit to the shoe shop where there is a meltdown, and you see the shoe shop lady thinking, this kid is a bit old to be behaving like this in public, and you get vibes. I'd like the shoe shop lady to read this book. It makes you more autism-friendly, because you can understand what's going on, and that understanding will make you more patient, kinder, more compassionate, and less 'what's that noise going on here?'"