“Saluton,” was how members of the Esperanto Society of New York greeted each other as they arrived at their holiday party in Midtown Manhattan.

They gathered to honor L.L. Zamenhof, the Polish-born physician who invented Esperanto, the language these club members study and speak.

Dr. Zamenhof was born on Dec. 15, 1859, and the club gathers every December to celebrate Zamenhof Day — Zamenhofa Tago, to Esperantists — something of a high holy day to club members.

“Today is our biggest holiday,” said the club’s president, Miko Brandini, who with more than a dozen other members celebrated in the meeting room of a church decorated with a sampling of Dr. Zamenhof’s books and some flowers displayed around a framed photograph of Dr. Zamenhof, who 130 years ago published the “Unua Libro” (“First Book”), laying out his international language or lingvo internacia.