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Science Communication

Expanding American Sign Language’s scientific vocabulary

A lack of signs for many scientific terms impedes deaf people’s entry into the sciences. Deaf scientists want to chip away at the barriers by developing more ASL signs for scientific terms.

by Leigh Krietsch Boerner
July 11, 2021 | A version of this story appeared in Volume 99, Issue 25
An illustration of scientist signing the word science

Credit: Glenn Harvey | The American Sign Language sign for ‘science’ is two closed fists with thumbs angled down, and each hand moves in small circles in opposite directions.


In brief

American Sign Language (ASL), which many deaf people in the US use to communicate, has a limited number of signs for advanced scientific terms. When people need to say something in ASL and there isn’t a sign for it, they often have to spell the term out letter by letter or use a sign that isn’t quite right conceptually. The lack of signs for advanced scientific terms significantly hinders deaf people’s entry into the sciences, and it isolates deaf scientists from their hearing peers. Groups of deaf scientists want to remove these obstacles by developing conceptually accurate ASL signs for scientific terms. But these groups are small and understaffed. As a result, new signs spread slowly.

In 2016, a summer internship changed Mandy Houghton’s life. At the time, she was a science teacher at the Florida School for the Deaf and the Blind. Harvard University invited her to attend a summer program at the Center for Integrated Quantum Materials (CIQM) to study science research and education.

Like many of her students, Houghton is Deaf. She uses mainly American Sign Language (ASL) to communicate. While taking science classes at Harvard that summer, the way the ASL interpreters signed some of the technical terms blew her mind.

Often, there isn’t an ASL sign for scientific terms. For example, Daniel Lundberg, a Deaf chemistry professor at Gallaudet University, estimates that about 80% of chemistry terms have no established sign. When people need to translate something into ASL and there isn’t a sign for it, they sometimes spell it out using the signs for the word’s letters, a practice called finger spelling. So during a class about the components of an atom, a deaf student would be lectured on P-R-O-T-O-N-S, N-E-U-T-R-O-N-S, and E-L-E-C-T-R-O-N-S.

If the word has another, colloquial meaning, people sometimes use that sign. For example, to sign “chemical reduction,” ASL users generally borrow the sign for a different meaning of the word—bringing two hands closer together to signify something shrinking. But in Houghton’s class, the interpreters used a sign that caught her attention. They signed something that looked more like “chemical increase,” which Houghton understood as an increase in the number of electrons, an accurate description of what chemical reduction is.

Credit: Rochester Institute of Technology/National Technical Institute for the Deaf/C&EN
ASLCore member Asma Sheikh shows the sign the ASLCore organic group developed for “ether”, “enantiomer”, and two versions of “tetrahedral”.

Even though using conceptually accurate signs can make a big difference for deaf students, their use is far from universal.

Deaf and deaf

While the use of these terms is still evolving, generally, uppercase Deaf refers to the cultural group of deaf people who share a signed language and beliefs about how they relate to hearing society. Lowercase deaf is now used as an all-inclusive term for any type of hearing loss, and it includes culturally Deaf people. In this story, we deferred to the preferences of those we interviewed. For more general usage and when we referred to a group of deaf people whose preferences we didn’t know, we used deaf.

When a sign doesn’t reflect the concept, deaf students can misunderstand the meaning or process the information incorrectly. Finger spelling or using nonconceptual signs makes lectures more complicated for deaf students. Houghton says that when she attends lectures, she often has to determine if what the interpreter is signing matches what the lecturer is saying, while simultaneously trying to follow the content of the lecture. She may have to ask the interpreter—sometimes in the middle of the lecture—how exactly the teacher said what the interpreter signed. And interpreters often don’t have knowledge of highly specialized fields, such as quantum science, which makes this exchange all the more difficult. Using conceptually accurate signs can avoid much of this confusion, Houghton says. At Harvard that summer, she says, “simply being able to focus and learn was a big change.”

When Houghton told hearing students and mentors at CIQM about the lack of signs for scientific terms in ASL, they were shocked. “They didn’t realize how many hurdles I had to be jumping over” to understand the lecture, she says.

Inspired by her experience with more-conceptual scientific signs during this internship, Houghton helped launch a project called Quantum Science in ASL to develop ASL signs for quantum physics terms. The project is a collaboration between CIQM and the Learning Center for the Deaf, a non-profit which specializes in ASL development.

And this group is not alone. Deaf scientists have recognized that this lack of signs for scientific terms significantly impedes deaf people’s entry into the sciences, as well as isolates deaf scientists from their hearing peers. These deaf scientists want to chip away at the barriers by developing more ASL signs for scientific terms. They’re devising signs that represent the concepts behind the terms. But because these groups are small and separate from one another, deaf people and interpreters haven’t widely adopted the new signs, which prolongs communication struggles for deaf students and scientists. Houghton and others think that to make significant, lasting progress on ASL signs for scientific terms, more deaf people need to get involved to ensure that the solutions work for the whole community.

Isolating barriers

Deaf chemistry professor Daniel Lundberg gives students instructions in ASL during a general chemistry lab at Gallaudet University in 2015.
Credit: Office of University Communications, Gallaudet University
Deaf chemistry professor Daniel Lundberg gives students instructions in American Sign Language during a general chemistry lab at Gallaudet University in 2015.

For the academic year 2015–16, the National Deaf Center on Postsecondary Outcomes found that 1.1% of hearing students studied the physical sciences at colleges and universities in the US. For deaf and hard-of-hearing students, it was 0.8%. These numbers illustrate what many deaf scientists already know: multiple barriers discourage deaf people from going into the sciences.

Fewer deaf people majoring in the sciences lead to fewer deaf professional scientists. And the lack of deaf scientists creates a negative feedback loop. “If you don’t see people that look like you, speak like you, live like you working and doing those things, you will assume it’s impossible,” Houghton says.

She recalls how her students in Florida said they hated science. But when she shared her own research with them, their opinions changed. “I think it was very inspiring for some of the students that I worked with to see someone like me, who is Deaf and signs like them, prove that it can be done,” she says.

Even for deaf people who continue to study science, communication issues remain a source of frustration and isolation. Graduate school in the sciences is already a challenge by its nature, but when there’s no one in a deaf student’s lab group or whole graduate program who can sign, it can be very isolating. “It’s important to have someone to bounce your ideas off of, and deaf people oftentimes are so siloed,” Houghton says.

While in graduate school, Alicia Wooten, a Deaf biology professor at Gallaudet and one of the cocreators of the ASL science, technology, engineering, and mathematics (STEM) site Atomic Hands, didn’t have an interpreter in her lab. “It was a huge challenge,” Wooten says. “Deaf and hard-of-hearing academics are sometimes left out of communication.” Writing down what you want to say for hearing lab mates can be slow and awkward, especially since written English is a second language for some deaf people. Hearing lab members can gain new techniques and help colleagues troubleshoot problems by overhearing conversations. Deaf students can’t take part in these conversations, even if they have the expertise.

Still, one of the fundamental issues facing deaf people interested in the sciences is that it’s hard to talk about the science itself because the signed terminology to describe some concepts is limited.

This limitation affects a deaf scientist’s ability to have meaningful experiences at scientific conferences. “I hate going to scientific conferences,” Gallaudet’s Lundberg says. The conference organizers usually provide interpreters, but the quality of these interpreters can vary greatly. In addition, these interpreters don’t know the signs that Lundberg has established and uses in his research, so he has to resort to finger spelling to the interpreter during informal chats with colleagues. So the people he’s talking with may not get all the information that Lundberg wants to convey. “By the way [my colleagues] are looking at me, I know that they’re thinking, ‘That doesn’t sound like Dan,’ ” he says. “Obviously, the interpreters are not doing an accurate interpretation of me.”

As a doctoral student, Lundberg once brought his school’s interpreters along. That was the only good conference he’s ever been to, he says. But it was “terrifically expensive” because the school had to pay for the interpreters’ plane tickets and room and board. The main purpose of a conference is to network, Wooten says. “It doesn’t happen in the same way when deaf people go.”

Laureen Summers, from the office of Science, Technology, and Disability of the American Association for the Advancement of Science (AAAS), says the AAAS provides interpreters and real-time captioning for sessions at its annual meetings. When possible, the meeting organizers send information from the speakers to the interpreters in advance so that they can prepare for talks. The AAAS did not specify whether the interpreters it provides have experience signing scientific content or have science backgrounds. The American Chemical Society, which publishes C&EN and hosts scientific meetings, provides computer-assisted captioning and ASL interpreters for all meeting attendees who ask for them. Paula Christopher, program manager at the Office of Diversity, Equity, Inclusion, and Respect at ACS, says the society has not previously looked into ASL interpreters’ science backgrounds but may do so in the future.

ASL basics

More effective ways to talk about science in sign language could help deaf scientists overcome some of the barriers they face. But fully appreciating the challenges of communicating technical information in ASL requires understanding that ASL is not a signed form of English. It’s a distinct language, with specific rules and grammar.

When there’s a new phenomenon in English, people tend to create a new word for it. “ASL tends to use agglutinative structure, which means that the signs are composed of different signs, which do not change much when strung together to make a word,” says Jon Henner, a deaf linguist specializing in ASL at the University of North Carolina at Greensboro. “Making new words in ASL is really just putting together different signs.” ASL is structured more like Japanese or Turkish, he says. That means ASL isn’t always intuitive for the English-hearing-and-speaking population.

In addition to being a distinct language, ASL is also the first language for many deaf people, especially those who were born deaf. “There are many, many deaf people whose understanding of English as a second language does not equal their understanding of ASL as a first language,” says Jeanne Reis, a hearing ASL interpreter and director of ASL Clear, a sign-developing project aimed at K–12 students. While most hearing people have no particular barriers to learning a second language, deaf people can’t hear the spoken language around them, making it harder to connect meaning with written words on a page.

The fact that in the US, English is some deaf people’s second language makes finger spelling scientific terms more of a problem than just being a clunky way to communicate. It’s as if you’re a native English speaker and know Spanish as a second language, and each time a lecturer mentions “titration,” the interpreter spells out V-A-L-O-R-A-C-I-Ó-N. Interspersing two languages in a single lecture can be jarring and confusing for students. Signs for scientific terms would make understanding much easier for deaf students, Reis says.

When you’re talking about developing signs, it’s not as if you can just create them, and overnight you have a bunch of signs” people start using.
Alicia Wooten, Deaf biology professor at Gallaudet University and cocreator of Atomic Hands

So why aren’t there many ASL signs for scientific terms? The reason, in part, has to do with the history of sign language.


In the late 19th century, a movement started by hearing people called oralism sought to change deaf education. Those leading this charge, including Alexander Graham Bell, who promoted the eugenic idea that deaf people should not marry each other, thought that instead of using ASL, which was not viewed as a legitimate language, deaf people should read lips and talk to better assimilate into hearing society. In 1880 in Milan, the members of the International Congress on Education of the Deaf—all of whom were hearing—voted to ban sign language. Oralism’s policies not only forced speech on deaf people but also may have hindered deaf children’s linguistic and cognitive development, Houghton says. “For years, deaf students were not allowed to sign in schools and would have their hands slapped if they were caught signing,” she says.

In the early 1960s, linguist William Stokoe published a paper that began to convince people that ASL is a true language. As a result, oralism’s dominance in deaf education started to wane. Oralists’ nearly century-long condemnation of the open use of ASL delayed both the language’s development and deaf people’s ability to contribute to society. But as more deaf people began participating in a wider range of fields, including in the sciences, the demand for technical signs shot skyward. Houghton’s project, and the others like it, aim to fill this science-shaped hole in ASL.

Developing signs

Rochester Institute of Technology (RIT) is home to one of the groups of deaf scientists working on new ASL signs. RIT is associated with the National Technical Institute for the Deaf (NTID), but not all the students at the university are deaf. RIT makes interpreters available for classes with deaf students, but the interpreters change often, says Asma Sheikh, a Deaf scientist at Harvard Medical School. She recently completed her bachelor’s degree in biomedical sciences from RIT. Students might negotiate signs for science terms for the interpreter in one class session, but the next session might have a different interpreter using different signs.

Credit: Rochester Institute of Technology/National Technical Institute for the Deaf/C&EN
The signs the ASLCore organic group developed for SN1 and nucleophilic acyl substitution reactions mimic the mechanism of each.

This inconsistency caused another Deaf RIT student, Kaitlyn Clark, to struggle during organic chemistry classes. Clark says she was frustrated because she could understand the scientific concepts explained in the lecture but not how the interpreters were signing the information. Eventually, Sheikh’s class got a consistent interpreter named Todd Thieu who had interpreted for organic chemistry before and understood the concepts. “We started negotiating a common vocabulary,” Sheikh says.

As a result, the small group of deaf students always had the best grades in class. This got the attention of the professor, Christina Goudreau Collison. Along with tutor Jennifer Swartzenberg, she encouraged the students to develop and record a series of ASL signs for organic chemistry. The group of deaf students got together twice a week for over a year to develop these signs, Sheikh says. “We’d be there for hours late at night. We were all really invested,” she says. “It was a real passion project.” Many of these signs are now posted online by ASLCore, a group of interpreters and deaf students based out of NTID that has developed advanced ASL signs in several disciplines.

Deaf scientists think about multiple factors when they develop scientific signs, Houghton says. First, they must evaluate whether the sign complies with the linguistic rules of ASL. Good signs will follow the patterns and parameters of ASL in terms of the shape of the signer’s hands, how the sign moves, and where in space it’s signed. “It has to follow those ASL rules,” Houghton says. “If it doesn’t, it doesn’t feel right.”

Next, deaf scientists need to assess how conceptually accurate the sign is. Sometimes a sign that follows the linguistic rules and is conceptually accurate already exists in ASL. When Houghton’s group found one of those signs for quantum physics terms, it left the sign as is. “If it’s something that already makes sense and works perfectly in conversation, that’s not something that we would modify,” she says. But if it doesn’t follow the rules or is confusing, that’s when the work starts.

One way a sign might be conceptually inaccurate is if it’s an anglicized sign, meaning it’s based on how something is spelled in English, ASL Clear’s Reis says. For example an older sign for “atom” is a signed letter “A” circling in the air. “This is not at all what an atom is” conceptually, she says.

Credit: Rochester Institute of Technology/National Technical Institute for the Deaf/C&EN
Sheikh signs “steric hindrance.” The ASL Core group designed the sign to depict the two curves often shown in textbooks to denote two atoms repelling each other.

The organic chemistry ASLCore team drew inspiration from the images used in the students’ textbook, Sheikh says. “We wanted to be able to represent organic chemistry terms in a way that was simple and easily understandable.” This means not only how things look, statically, but also the way things move, Sheikh says. For example, the sign the team developed for steric hindrance was two curved hands, placed back to back, tapping against each other. “It represents the two curves that you often see as a symbol in textbooks” for two atoms running into each other, Sheikh says.

Sign developers also have to consider the context in which a term is used and how that affects its meaning. For example, one ASL sign for “electron” shows a single finger wiggling in the air. This makes sense if you’re talking about free electrons, Gallaudet’s Wooten says. But in a general chemistry class, when you’re thinking about electrons orbiting a nucleus in an atom, that sign is not as conceptually accurate. In that case, it makes sense to use the ASL sign for electron that shows a finger circling a closed fist.

Because of differing contexts, there can be multiple signs for the same concept. Just on ASLCore alone, there are five signs for the word “molecule”: one in chemistry, one in physics, and three in biology. The organic chemistry team didn’t make new signs for a lot of the concepts already presented in the physics or biology sections. But the way the other teams signed “molecule” didn’t quite match what the chemists wanted to convey, Clark, a member of the ASLCore group, says. Conceptually, the biology signs are more based on large biomolecules like proteins, while the physics sign, two cupped hands rotating relative to each other, didn’t show how a molecule might interact with other molecules. So the chemists developed their own sign, depicting two molecules near each other. “When we look at a molecule, we’re not always looking at the molecule by itself,” Clark says. “It’s reacting with other molecules.”

Credit: Rochester Institute of Technology/National Technical Institute for the Deaf/C&EN
The organic chemistry, physics, and biology groups at ASLCore each developed their own signs for “molecule” based on how each discipline explains and talks about them.

Which sign to use?

With multiple groups creating scientific signs and old signs still floating around, how do people know which one to use? This question hits upon an issue that all languages face, spoken or signed: no one person or group controls a language.

For example, consider the sign for “bacteria.” In the past, people used the sign for “bug,” as in an insect, similar to how the word is sometimes used in English. ASL now has a separate sign for “bacteria,” but some scientists continue to use the one for “bug” because it’s ingrained, Wooten says. “People just like some signs better than others. They’re easier to sign or more intuitive or fit the context better,” she says.

Because of this variability in the use of signs, professors have to work with their students to decide which signs to use for each class, Wooten says. There are even differences in the same university across programs, Lundberg says. Wooten’s intro to biology class and Lundberg’s intro to chemistry class usually include the same students at the same time. As a result, the students may see two signs for the same concept. Sometimes the students protest when a professor introduces a sign they’re not used to. When she used one of the signs for “electron,” students didn’t like it at first, Wooten says. “They asked me to actually go back and to use a sign that had been more of an original sign.”

We are using [ASL] every day, in every aspect of our lives. It makes sense that any change would come from us.
Mandy Houghton, Deaf principal investigator, Quantum Science in ASL Project at The Learning Center for the Deaf and Harvard’s Center for Integrated Quantum Materials

Professors in the two departments try to get everybody on the same page, but figuring out the terminology takes extra meetings and time. And even then, the professors slip occasionally. “I’ve even noticed myself in class where I’ll use some older sign,” Wooten says. “I have to catch myself and back up.”

The newer signs under development are part of an ongoing conversation in the deaf community, she says. When signs are introduced, either people use them, or they don’t. “When you’re talking about developing signs, it’s not as if you can just create them, and overnight you have a bunch of signs” people start using, Wooten says.

The projects on scientific signs aim to provide a starting place for language development and for the evolution of the language, CIQM’s Houghton says. “We depend on the community, deaf people, ASL users to see if they adopt and use the signs that we’re creating,” she says. “And to see whether the information discussed using these signs actually enhances knowledge transfer and the conversation itself.”

Nobody has a specific right to a final say on a particular sign “because language belongs to all those who use it,” Wooten says. A new sign might take off in the community, she says. Or maybe it doesn’t quite work and will either drop out of use or change. In some cases, signers decide over time that the sign is misleading or too long, and people may drop a portion of it. “Then the information becomes more efficient, more clear,” Houghton says.

Sometimes useful signs pop up and then feed off one another. One of the math signs that ASL Clear developed was for “fraction.” The old sign was anglicized: the sign for the letter “F” over then under a finger held horizontally, Reis says. The ASL Clear team swapped in the sign for “digit” instead of “F.” “If you put this handshape over that handshape, now what you’re representing is an unknown digit over an unknown digit, which is the actual definition, right?”


This sign later inspired the one for “ratio” developed by the Quantum Science in ASL group. While having a conversation, “we’re spelling ‘ratio’ over and over and over,” Houghton says. Then one person used the sign for “fraction” but tipped it on its side to show a digit next to a digit, separated by a vertical finger. “We were all like, ‘Whoa, that actually makes a lot of sense,’ ” Houghton says. Because the sign for “fraction” was already in their minds, the sign for “ratio” felt comfortable and easy to use, she says.

Many of the people involved in these ASL groups think that the effort needs more deaf people developing signs for scientific terms. But it’s not a lack of funding preventing people from establishing more of these groups. “There are people out there who want to collaborate with us and support this work,” Houghton says. But they just don’t have the time.

The people involved in these projects also agree that deaf people should lead the efforts to create more signs. Those developing these signs should have the language knowledge, the native fluency, and the content knowledge, ASL Clear’s Reis says. Most interpreters don’t have specialized science knowledge, and while they know ASL, it’s often not their primary language.

When deaf people are the ones to create solutions for scientific signs, they are able to take ownership of their language and culture. For many decades, hearing teachers have told deaf people what should be done in education and have often pushed aside and marginalized them, Houghton says.

So for a long time, hearing-based society has made deaf people feel ashamed about their language and culture. They’ve been made to feel that their language is not as good as English. And that’s why Houghton and others want deaf people to lead the way in making it easier to communicate science via ASL. “We are using [ASL] every day, in every aspect of our lives,” she says. “It makes sense that any change would come from us.”

Interviews with Henner, Houghton, Lundberg, Sheikh, and Wooten were conducted using an ASL interpreter.


This story was updated on July 13, 2021, to correct the date of the photograph of Daniel Lundberg. It was taken in 2015, not 2019.

This story was updated on July 14, 2021, to correct Paula Christopher's title. Christopher is a program manager at the Office of Diversity, Equity, Inclusion, and Respect at ACS, not a program manager of diversity planning and strategy.

This story was updated on July 23, 2021, to correct the name and drawn mechanism of one of the reactions signed in the second sign language video. While the original version of the video labeled the second sign as "1,2-addition," which is the label ASLCore gives it, the more commonly used organic chemistry term would be “nucleophilic acyl substitution.” The original video also showed the mechanism of a 1,2-addition to a diene instead of a nucleophilic acyl substitution for that sign. The video has been updated to indicate that name and mechanism.


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