About a third of people with autism cannot communicate using speech, and most of them have never been able to find an effective alternative. However, a new study by researchers at the University of Virginia shows that many of these people are literate, which means they can learn to express themselves through writing.

The study, published in the journal Autism, reports that five times as many non-speaking autistic adolescents and adults demonstrated proficiency in language and writing than previous assessments of their abilities would suggest. This finding has important implications for the millions of people with autism around the world who speak little or no language and are often considered unable to acquire literacy skills.

"If we assume that a person who can't speak doesn't understand, it limits the opportunities we open up to them - we may not even try to find out what they understand," Vikram Jaswal, professor of psychology at the University of Virginia, told the study's lead author. - Our study shows that the language, learning and literacy abilities of non-speaking autistic people have been seriously underestimated."

Researchers addressed a fundamental literacy question: whether non-speaking people with autism respond to letters, words and sentences in the same way as literate people without autism. They developed a method that required participants to click on letters displayed on a tablet as soon as those letters lit up. In some cases, the letters lit up in a sequence that included sentences previously spoken aloud, and in other cases, the letters lit up in a nonsensical sequence.

According to Jaswal, the results of the study are striking because they show that although most of the study participants had not received formal literacy instruction, many of them had an idea of how written language works.