Gwyneth Rost examines a surprising picture of the prison population in this country.

Rost, a Ph.D. candidate in speech pathology, once read that 60 to 80 percent of prisoners are language impaired. That striking statistic prompted this native of Denver, CO to wonder how many innocent people are in prison.

“Maybe they don’t understand what the law is or maybe they don’t have the language skills to talk to a policeman in a way that doesn’t falsely incriminate them,” Rost said.

Rost and her UI mentor, Karla McGregor, are addressing this concern in a research paper Miranda Rights Comprehension in Young Adults with Specific Language Impairment, which she is preparing for journal approval.

The researchers studied 34 students at the UI and Kirkwood Community College in Cedar Rapids, ranging in age from 18 to 25. Half were language impaired and half not. These two groups were matched in gender, age, ethnicity, and socioeconomic status.

The subjects, half of whom were male and half of whom were female, were given a series of tests on Miranda warning comprehension. According to the test writers, only three of 17 language impaired participants scored high enough to be considered competent enough to waive their Miranda rights. One of the Miranda rights is the right to competent legal counsel.

Sixteen of 17 non-language impaired subjects scored high enough to be considered competent enough to waive their Miranda rights. “We’re feeling pretty confident that the language ability really does predict the Miranda rights comprehension pretty strongly,” said Rost, a former school speech-language pathologist. “This paper shows that most Miranda warnings are not explaining Miranda rights to people.”

These findings are particularly relevant given a Supreme Court ruling in June stating that one cannot waive Miranda rights by remaining silent. One must actually verbalize the desire to remain silent.

Rost believes this research provides a new view of inmates in our nation’s prisons. “We rarely talk about what makes a person more likely to be caught or incarcerated,” Rost said. “Having language impairment likely represents a risk for incarceration.”

Rost has observed that language impaired people are good at pretending they know what is going on in a given situation, which makes identifying these individuals quite challenging for the legal and law enforcement communities. “You can’t really pinpoint the cause of the problem because they hear normally and they’re intelligent,” said McGregor, a UI professor who directs the Word Learning Lab. “They don’t have any physical abnormalities. It’s hard to understand why they’re having these language learning difficulties.”

In light of these research findings, what can be done to prevent language impaired people from falsely incriminating themselves? “A long-term implication would be reconsideration of the Miranda warning words,” McGregor said. “There isn’t really a standard; it varies from jurisdiction to jurisdiction. It’s not necessarily the one you hear on television.

“Something we are more in control of in our profession is understanding that these are more lifelong needs and those affected might need intervention on a continued basis. We need to think about how to ramp up that intervention.”