This is the VOA Special English Health Report.

Deaf people may have no trouble communicating English words through American Sign Language, or ASL. But studies of ASL users show that, on average, educated deaf adults are likely to read at the level of a nine-year-old.

The explanation has always been that this is because they never learned to connect letters with sounds. But a recent study shows that deaf readers are just like other people learning to read in a second language. Linguist Jill Morford led the study.

JILL MORFORD: "The assumption has always been that the problems with reading were educational issues with what's the right way to teach reading when you can't associate sounds with letters. But what we're finding is that all this time we've been ignoring the fact that they're actually learning a new language."

Ms. Morford is a professor at the University of New Mexico and part of a research center at Gallaudet University in Washington. Most students at Gallaudet are deaf; the center studies how deaf people learn and use language.

Professor Morford says signers are like English learners whose first language uses a different alphabet.

JILL MORFORD: "Anyone who has a first language that has a written system that's very different than English, like Arabic or Chinese or Russian, knows that learning to recognize and understand words in English is much more challenging than if you already speak a language that uses the same orthography."

The orthography is the written system and spelling of a language. Of course, with signers, their first language has no written system at all, just hand gestures. Gallaudet professor Tom Allen explains what effect this has on reading.

TOM ALLEN: "We're not dealing with representations in the brain which are primarily auditory. You know, people when they read, they kind of hear -- there's a silent hearing going on when you read a word, when a hearing person reads a word. When a deaf person reads a word, there's not. They see the word and there's some kind of an orthographic representation. And some of the research in our center has shown that when deaf readers read an English word, it activates their sign representations of those words."

Signers can face the same problems as other bilingual people. Their brains have to choose between two languages all the time. Take the words "paper" and "movie." Their spelling and meaning are not at all similar. But, as Professor Allen points out, the signs for them are.

TOM ALLEN: "The sign for paper, you hold one hand flat and you just lightly tap it with a flat palm on the other hand, and you do that a couple times and that means paper. Now, movie is, like, very similar. One of the hands keeps a flat hand shape and it just kind of lightly moves back and forth as if it were a flickering image on a screen."

The study is in the journal Cognition.

And that's the VOA Special English Health Report, written by Kelly Nuxoll. To learn about other research on bilingualism, go to voaspecialenglish.com. And you can find captioned videos of our reports on the VOA Learning English channel on YouTube. I'm Steve Ember.

orthography: the system of spelling in a language（文字的）拼寫體系，拼寫法

Related stories:

Inside the complex worlds of deaf culture

Deaf-Blind Awareness Week

Are people who speak more than one language smarter?

研究：語言的轉(zhuǎn)換可能帶來個性轉(zhuǎn)變

（來源：VOA 編輯：崔旭燕）