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While sign language interpreting is not an area of specialization for me, I've admired sign language interpreters ever since I attended the Critical Link Conference in Montréal, at which interpreters for both signed and spoken languages gathered. I had seen sign language interpreters at work previously, but at that event, there were interpreters on stage for so many different sign languages, each one different from the next, and it was a fascinating sight to behold, something along the lines of a visual chorus.
Many monolinguals, and even many spoken language interpreters, are surprised by the large number of sign languages that exist. It is common for people to assume that sign language is "universal" across the globe. Not so!
There are at least 25 sign languages used in Africa, about 30 sign languages used in Asia, approximately 33 sign languages in Europe, roughly 6 sign languages used in the Middle East, and 22 sign languages used in the Americas.
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Across the pond, at one point in history, there was even a Martha's Vineyard Sign Language that thrived at one time due to the unusually high number of deaf inhabitants of the island. In one region of a town called Chilmark, as much as a quarter of the population was deaf. On the island as a whole, about 1 in every 155 people was deaf. This is documented in a book called Everyone here spoke sign language: Hereditary deafness on Martha's Vineyard by Nora Ellen Groce, available here. As schools for deaf children opened on the mainland, many families migrated away from the island, and this sign language soon became extinct.
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Often, when I am conducting research on interpreting, I come across articles with helpful information for sign language interpreters, although much of the information usually applies to spoken language interpreters as well. Even when it doesn't apply, it's always interesting.
One virtual treasure trove of information is David Bar-Tzur's site, The Interpreter's Friend. There are some fascinating articles on interpreting for spiritual/religious topics, many of which I believe would be of great interest to all interpreters. There is also a tremendous list of resources.
May the knowledge-sharing continue. All colleagues from the sign language interpreting community are welcome to participate in this project.