The sign language interpretation at Tuesday’s Nelson Mandela memorial service in Johannesberg, South Africa, was apparently so dismal that interpreter Thamsanqa Jantjie was accused of making his signs up as we went along. Wilma Newhoudt-Druchen, the first deaf woman in South Africa’s parliament, called the interpretation “rubbish,” and Francois Deysel, a South African sign language interpreter, tweeted that Jantjie was “making a mockery of our profession.”

In light of the controversy, we asked Lydia Callis, the New York City-based sign language interpreter who gained fame for her television appearances alongside Mayor Bloomberg during Hurricane Sandy, for her take. Though as an American Sign Language interpreter, Callis wasn’t able to weigh in on the mechanics of South African Sign Language and the specific ways in which Jantjie’s interpretation may have went wrong, she did offer some insight into the nuances of sign language, and the ways in which the culture of a place can influence how the deaf communicate.

(The AP’s report that Thamsnqa Jantjie may have been having a schizophrenic episode had not yet come to light at the time of our interview.)

Theres a large cultural assumption that American Sign Language is a universal sign language, but that isn’t the case.

Yes, it is a very common assumption that American Sign Language is universal, but it’s not. Everybody has their own traditions and customs, and you want that to come through the language.

It even breaks down within America. For a perfect example, when I was interpreting for Mayor Bloomberg during Hurricane Sandy,  people in Texas were like, “Whoa, this interpreter needs to slow down a little bit.”

But that’s just New York’s style. Different regions across the country have different styles, different slang, you could call it, or accents, within our sign language.

Also, there are unqualified interpreters out there, but every interpreter should only accept jobs that they’re familiar with. If you’re in a medical setting, and the speaker is a doctor, the interpreter has to be familiar with medical jargon, or if you’re with a business, representing a brand, the interpreter needs to know about that brand.

How was this allowed to happen? Is it indicative of a larger problem the mainstream media has in communicating with the deaf community?

It’s not just the mainstream media sources. It’s the general public.

During Hurricane Sandy, I really didn’t understand why such a big deal was being made of my interpretations. When I sat back and reflected on everything that happened, I realized it was a social media blitz. But the reason why it was a blitz was that people just don’t know much about deaf culture and about the language.

People seemed to be reacting to what they perceived as your liveliness or expressiveness while interpreting. But should those things be par for the course?

Of course, every interpreter is going to have a slightly different signing style. I’m a little more expressive, because I come from three generations of deaf family members, and that was my first language.

It’s just people not being educated. For hearing people, nonverbal communication is probably 60 percent of communication–your body language, your facial expressions, your gestures. Sometimes I look at a hearing person and I think that they’re deaf, because they’re communicating so much nonverbally.

I have my facial expressions, I have my gestures, I have my body language, and then, with the sign language on top of it, it all comes together to make it seem my communication is overdramatic. But it’s not. It’s just the language, and some interpreters are more expressive than others.

Often times we’re asked who we’re interpreting for. For example, during Hurricane Sandy, some people said, “Mayor Bloomberg–he has such a straight face.” But you have to look at the content. He was talking about something serious–a dangerous, life-or-death situation–and that’s what came across in my interpretation.

What are you doing now, after the limelight?

I don’t want to see my deaf nieces, who are children right now, going through the same things that my family went through 50 years ago. So I’m going out and teaching cultural sensitivity to the hearing community, but also teaching deaf people how to know their rights. Before I’m an interpreter, I’m a member of the deaf community, because that’s the community I grew up in.