Carolyn McCaskill remembers exactly when she discovered that she couldn’t understand white people. It was 1968, she was 15 years old, and she and nine other deaf black students had just enrolled in an integrated school for the deaf in Talledega, Ala.

When the teacher got up to address the class, McCaskill was lost.

“I was dumbfounded,” McCaskill recalls through an interpreter. “I was like, ‘What in the world is going on?’ ”

The teacher’s quicksilver hand movements looked little like the sign language McCaskill had grown up using at home with her two deaf siblings and had practiced at the Alabama School for the Negro Deaf and Blind, just a few miles away. It wasn’t a simple matter of people at the new school using unfamiliar vocabularly; they made hand movements for everyday words that looked foreign to McCaskill and her fellow black students.

So, McCaskill says, “I put my signs aside.” She learned entirely new signs for such common nouns as “shoe” and “school.” She began to communicate words such as “why” and “don’t know” with one hand instead of two as she and her black friends had always done. She copied the white students who lowered their hands to make the signs for “what for” and “know” closer to their chins than to their foreheads. And she imitated the way white students mouthed words at the same time as they made manual signs for them.

Whenever she went home, McCaskill carefully switched back to her old way of communicating.

What intrigues McCaskill and other experts in deaf culture today is the degree to which distinct signing systems — one for whites and another for blacks — evolved and continue to coexist, even at Gallaudet University, where black and white students study and socialize together and where McCaskill is now a professor of deaf studies.

Five years ago, with grants from the National Science Foundation and the Spencer Foundation, McCaskill and three fellow researchers began to investigate the distinctive structure and grammar of Black American Sign Language, or Black ASL, in much the way that linguists have studied spoken African American English (known by linguists as AAE or, more popularly, as Ebonics). Their study, which assembled and analyzed data from filmed conversations and interviews with 96 subjects in six states, is the first formal attempt to describe Black ASL and resulted in the publication last year of “The Hidden Treasure of Black ASL.” What the researchers have found is a rich signing system that reflects both a history of segregation and the ongoing influence of spoken black English.

The book and its accompanying DVD emphasize that Black ASL is not just a slang form of signing. Instead, think of the two signing systems as comparable to American and British English: similar but with differences that follow regular patterns and a lot of variation in individual usage. In fact, says Ceil Lucas, one of McCaskill’s co-authors and a professor of linguistics at Gallaudet, Black ASL could be considered the purer of the two forms, closer in some ways to the system that Thomas Hopkins Gallaudet promulgated when he founded the first U.S. school for the deaf — known at the time as the American Asylum for Deaf Mutes — in Hartford, Conn., in 1817.

Mercedes Hunter, a hearing African American student in the department of interpretation at Gallaudet, describes the signing she and her fellow students use as a form of self-expression. “We include our culture in our signing,” says Hunter, who was a reseach assistant for the project, “our own unique flavor.”

“We make our signs bigger, with more body language” she adds, alluding to what the researchers refer to as Black ASL’s larger “signing space.”

No universal language

When she tries to explain how Black ASL fits into the world of deaf communication, Lucas sets out by dispelling a common misconception about signing.

Many people think sign language is a single, universal language, which would mean that deaf people anywhere in the world could communicate freely with one another.

Another widely held but erroneous belief is that sign languages are direct visual translations of spoken languages, which would mean that American signers could communicate fairly freely with British or Australian ones but would have a hard time understanding an Argentinian or Armenian’s signs.

Neither is true, explains J. Archer Miller, a Baltimore-based lawyer who specializes in disability rights and has many deaf clients. There are numerous signing systems, and American Sign Language is based on the French system that Gallaudet and his teacher, Laurent Clerc, imported to America in the early 19th century.

“I find it easier to understand a French signer” than a British or Australian one, Miller says, “because of the shared history of the American and French systems.”

In fact, experts say, ASL is about 60 percent the same as French, and unintelligible to users of British sign language.

Within signing systems, just as within spoken languages, there are cultural and regional variants, and Miller explains that he can sometimes be stumped by a user’s idiosyncracies. He remembers in Philadelphia coming across an unfamiliar sign for “hospital” (usually depicted by making a cross on the shoulder, but in this case with a sign in front of the signer’s forehead).

What’s more, Miller says, signing changes over time: The sign for “telephone,” for example, is commonly made by spreading your thumb and pinkie and holding them up to your ear and mouth. An older sign was to put one fist to your ear and the other in front of your mouth to look like an old-fashioned candlestick phone.

So it’s hardly surprising, Miller says, that Americans’ segregated pasts led to the development of different signing traditions — and that contemporary cultural differences continue to influence the signing that black and white Americans use.

Some differences result from a familiar history of privation in black education. Schools for black deaf children — the first of them opened some 50 years after the Hartford school was founded, and most resisted integration until well after the Brown v. Board of Education decision of 1954— tended to have fewer resources. Students were encouraged to focus on vocational careers — repairing shoes or working in laundries — rather than pursuing academic subjects, Lucas says, and some teachers had poor signing skills.

But a late-19th-century development in the theory of how to teach deaf children led, ironically, to black students’ having a more consistent education in signing. The so-called oralism movement, based on the now controversial notion that spoken language is inherently superior to sign language, placed emphasis on teaching deaf children how to lip-read and speak.

Driven by the slogan “the gesture kills the word,” the oralism theory was put into practice in the United States predominantly in white schools. Black students, Lucas says, were left to manage with their purely manual form of communication.

Ultimately rejected by people who felt it prevented deaf people from developing their “natural,” manual language, oralism fell out of favor in the 1970s and ’80s, but white signers continued to mouth words. That was one of the key differences McCaskill noted when she joined the integrated Alabama School for the Deaf. And the distinction is still evident today, Lucas says, among older signers.

The challenges of interpretation

Regional and cultural differences in signing are a constant challenge for interpreters, according to Candas Barnes, a professional interpreter based at Gallaudet, who describes the role as a “continual decision-making process.”

Sometimes a black public figure might shift into African American English and back, as Oprah sometimes does, to make a rhetorical point. The interpreter, Barnes says, may or may not switch into Black ASL, “depending on who the audience is.” A primarily white audience may not understand Black ASL, she points out.

And there’s no guarantee that every black member of an audience would understand, Barnes says. But she says interpreters for the Congressional Black Caucus’s annual legislative conference “are more inclined to follow along” because the audience would most likely be African American.

Miller, the disability rights lawyer, sometimes finds it a challenge “to find the appropriate interpreter for a particular person.” Interpreters, he says, “need to be able to communicate certain expressions and make sure they don’t mistake one sign for another and inadvertently completely change the meaning of the deaf person’s statement.”

The kinds of confusion that can come up, says Lucas, include the sign for “bad,” which can mean “really good” in Black ASL — an example of a usage that migrated from spoken black English. Similarly, in Black ASL, the sign for “word” can mean “That’s the truth!” — though Lucas says white signers wouldn’t use it in that way.

And Mary Henry Lightfoot, a former board member of the National Alliance of Black Interpreters who works at Gallaudet, says that features associated with Black ASL, such as its larger signing space and “facial grammar,” sometimes cause interpreters to misunderstand the message. “If you’re not used to that as part of the language, you can misinterpret,” she says.

“I’ve heard African American signers say, ‘Don’t make assumptions about what I’m saying based on what I look like.’ ”

‘Signing like the white students’

There’s little evidence of Black ASL in the Gallaudet University classroom when McCaskill leads a diverse group of about 20 students in a discussion of “The Dynamics of Oppression,” a course that examines oppression across different cultures and explores parallels in the deaf community. In the classroom, just as in a professional setting, Lucas says, students and teachers generally employ a formal, academic norm, much as would be the case with spoken English.

But as students break into smaller discussion groups, their signing becomes more colloquial. They refer to regional differences in signing and occasionally stop to discuss a sign that is unfamiliar to one of them.

And when a smaller group of black students meets to describe and demonstrate the distinctive flavor of Black ASL, they refer emotionally to their attachment to their own brand of signing and how it reflects their identities as African American members of the deaf community.

“It shows our personality,” says Dominique Flagg, through an interpreter.

“Our signing is louder, more expressive,” explains Teraca Florence, a former president of the Black Deaf Student Union at the university, where 8 percent of the student body is African American. “It’s almost poetic.”

Proud as they are of its distinctive rhythm and style, Flagg and the other students say they worry about assumptions others make about their signing. “People sometimes think I am mad or have an attitude when I am just chatting with my friends, professors and other people,” Flagg says.

Others express concern that Black ASL is sometimes seen as less correct or even stereotyped as street language, echoing a sentiment expressed by some African American signers interviewed for the book who describe the ASL used by white people as “cleaner” and “superior.”

It’s a familiar feeling for McCaskill, who remembers how she had to learn to fit in with the white kids at her integrated school all those years ago.

“I would pick up their signs,” McCaskill says.

And when she went home, she remembers, “friends and family would say, ‘Wait a minute, you’re signing like the white students. You think you’re smart. You think you're better than us.’ ”