Field of Science


To Dyslexics, English Sounds like a Foreign Language

How well can you identify other people's voices? Most of us are good at recognizing a familiar speaker we can't see. This skill works best, though, in our native tongue. And to the ears of a dyslexic person, everyone else may as well be speaking Chinese.

Dyslexia is usually described as a reading disorder. In school, a dyslexic kid will struggle to recognize words and parse sentences. She (or more often, according to some studies, he) might have assignments read aloud or receive prewritten class notes.

Underneath this difficulty with reading, though, may lie a failure to correctly process the sounds that make up words. To explore this theory, researchers at MIT had 16 dyslexic adults and older teens, as well as 16 non-dyslexics, listen to a series of recorded sentences. The voices they heard belonged to ten males, five speaking English and five speaking Mandarin Chinese (a language none of the subjects was familiar with). Subjects were trained on a computer to associate each of the 10 voices with a cartoon avatar. Then the test began: subjects listened to a series of 50 sentences and had to pick the speaker for each one.

Non-dyslexic subjects were much better at identifying the speaker when the sentences were in English. They picked the right avatar (out of the five possible ones) about 70% of the time in English, and only about half the time in Mandarin. Dyslexics, though, experienced no advantage with an English-speaking voice. They identified English speakers and Mandarin speakers equally, at about 50%, precisely as if English weren't their native language. Furthermore, the subjects with the most severe dyslexia fared the worst at identifying English speakers.

Voice recognition, the authors say, depends on our ability to analyze the phonetic pieces within each word and compare them to what we expect to hear. Different people's pronunciations will deviate from our expectations in different ways. When we don't have any expectations about those sounds, though--say, if we're hearing an utterly unfamiliar language--we have a harder time comparing the voices of different speakers. A dyslexic person may be lacking that internal dictionary of sound blocks for his or her native language. Instead of being processed invisibly in the brain, words must be scrutinized and decoded. School begins to resemble a foreign-language immersion class.

Dyslexia can encompass a range of symptoms. A related diagnosis, and one that sometimes goes along with dyslexia, is dysgraphia: an impairment in writing, rather than reading. Here, it's described by a 12-year-old reader of the magazine I edit; she left this comment on a discussion thread about what it means to be normal.
hi i am desgrafic, no its not contages and it is most sertenitly not my name. is a lerning disability, not two sereus thogh. it makes it hard to picture things in the mind, spell, follow derections, read, and a few other things like i hand cordination. its twin is dislecseo, its basickly the same. this isn't a desese and it's farly comin, and the best thing is you can get over it. it just makes it so you have to wurk a lot harder. and oh, did i mention hand righting, near imposiblely illegable. i used to spell cow C-A-W becase thats how i fenedickly chuncked it. there are some spetule scools set up (mostly privit) which foces on these disibityis. unforchinitly there is no cure exept a magick pill we call persestence, tack twise dally.
This girl single-handedly cured me of my habit of fixing all our commenters' spelling errors. I did it to keep kids from picking on each other's mistakes. But as soon as she started commenting, I threw in the towel.

Aside from being daunted by the task of interpreting and correcting all her words, I liked her comments the way they were. She was able to compose mature, interesting sentences--so much for a "writing disorder"--but approached English with an almost poetic naiveté (i hand coordination!). What's charming to me, though, illustrates the cognitive reality for kids with these disorders: At a certain level, they have no native language.

Perrachione, T., Del Tufo, S., & Gabrieli, J. (2011). Human Voice Recognition Depends on Language Ability Science, 333 (6042), 595-595 DOI: 10.1126/science.1207327

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