SPEAKING THROUGH AN INTERPRETER ON a three-way video call from a chilly Tel Aviv, Sara Lanesman, a linguist at Haifa University’s Sign Language Research Laboratory, signs with energetic motions that convey the intensity of what she felt during two formative moments of her life. The first: having to flee Algeria as a child with her family. The second: finding the country again through a sign language she didn’t know existed.

Several years ago, Lanesman and her mentor, the late linguist Irit Meir, were documenting the history of Israeli Sign Language (ISL). “We were interviewing subjects, asking them to do a simple picture-naming task,” Lanesman says. They asked a participant to sign “boy.” The 65-year-old volunteer, known to the research team by his initials, Y.Z., had immigrated to Israel from Algeria. His response caught their attention, Lanesman recalls. “He asked us: ‘Do you want me to use the sign I use with my friends, or the sign I use with my mother?’”

This unexpected question from the study participant would lead to the discovery of a unique, nearly-lost language that was hanging on right under their noses. For Lanesman, finding the unknown language was particularly poignant: It was born in an isolated and now lost Jewish community in the same country she had fled as a child.

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