Leonard Nimoy explained to the Yiddish Book Center Wexler Oral History Project how his idea for Mr. Spock‘s Vulcan hand gesture came about during a Jewish ceremony, how he incorporated the greeting into the Star Trek series and how it quickly became an international symbol throughout the world.
5 or 6 guys got up on the bimah – the stage in front of the congregation. They get their tallit over their heads and they start this chanting, I think it’s called Dukhanen, and my father said “don’t look”. So everybody’s got their eyes covered with their hands, their tallit over their faces or turned away, turned their back to these guys and I hear this strange sound coming from them. They’re not singers, they were shouters and dissonant – it was all discordant. …It was chilling, something major is happening here, so I peeked. And I saw them with their hands stuck out from beneath their tallit like this toward the congregation and I thought “wow”.
Here’s the full interview where Leonard Nimoy speaks Yiddish and tells the story of his family origins.