Writing is a system of human visual communication that represents language using signs and symbols. The human ability to write evolved from our ability to speak and since it is an evolutionary human invention, its underlying principle cannot be determined by the genetic code.

Talking and Writing are Independent, See How Brain Separates Our Ability to Talk and Write

Now, a team of researchers at Johns Hopkins University have found that writing and talking are two independent systems that someone who can’t write a grammatically correct sentence may be able say it aloud flawlessly. For example, when someone says, “The man is catching a fish.” The same person then takes pen to paper and writes, “The men is catches a fish.”

The team found the possibility of the part of the brain being damaged but leave the writing part unaffected and vice versa. This happens even when dealing with morphemes, a tiniest meaningful morphological unit of a language system including suffixes like “er,” “ing” and “ed.”

Their finding was published in the journal Psychological Science : Modality and Morphology – 
What We Write May Not Be What We Say 

Brenda Rapp, a professor in the Department of Cognitive Science in the Krieger School of Arts and Sciences, said in a statement – “Actually seeing people say one thing and — at the same time — write another is startling and surprising. We don’t expect that we would produce different words in speech and writing.”

“It’s as though there were two quasi-independent language systems in the brain.” Rapp added.

The researchers wanted to study how the brain incorporate skills of this type and its ability to organize knowledge of written language, because for spoken language there is a genetic blueprint and for written, there is not.

The researchers also wanted to study if written language and spoken language were dependent in literate adults. If it was, the researchers would have concluded that one would expect to see similar errors in speech and writing and if not, one might see that people don’t necessarily write what they say. To study this, the team studied five aphasic stroke victims.

Of these five victims, four had difficulties in writing sentences with the proper suffixes, but had few problems speaking the same sentences and one had trouble with speaking but no difficulty in writing.

When the researches showed the individuals pictures and asked them to describe the action portrayed in the pictures, they found that one of the individuals said, “The boy is walking,” but wrote, “the boy is walked.” And another said, “Dave is eating an apple” and then wrote, “Dave is eats an apple.”

Thus, the researchers were able to conclude that writing and speaking are supported by different parts of the brain and what you write may not be what you say and vice versa.

“We found that the brain is not just a ‘dumb’ machine that knows about letters and their order, but that it is ‘smart’ and sophisticated and knows about word parts and how they fit together,” Rapp said.

“When you damage the brain, you might damage certain morphemes but not others in writing but not speaking, or vice versa.”

The researchers hope the study opens eyes to a better means of treatment for those suffering from aphasia and helps educators to teach children effectively to read and write.