AMHERST — Conducting a tour of the National Yiddish Book Center, Aaron Lanksy, the center’s founder and president, had much to show off: a new wing that opened last year; an exhibit of Maurice Sendak’s work; a recording studio where visitors’ reflections on growing up Jewish are taped and archived; a new executive director; and an ongoing initiative to digitize thousands of Yiddish-language texts.

But there were less salutary signs, too.

The center was nearly devoid of walk-in visitors and its bookstore shuttered, albeit temporarily. Events listings for the coming weeks were virtually nonexistent. Membership has fallen from 25,000 to 15,000 in recent years. The dismissal of four staff members in December reflected tough economic times. And there are growing rumblings from critics who question Lansky’s managerial skills and institutional vision.

While the future of the 30-year-old nonprofit may not be in imminent jeopardy, these are anxious times for the center, which has collected and archived more than 1 million endangered Yiddish-language texts and garnered worldwide admiration for its cultural rescue mission.

A shift in focus to educational programs and to an emphasis on Jewish cultural studies in general (not just Yiddish studies) has not sat well with many who’ve worked with or supported the center over the decades. The recent layoffs, they say, raise more troubling questions about what the center aspires to be in its fourth decade.

“It’s not really upheaval and certainly hasn’t felt that way here, despite some vituperation around the edges,’’ Lansky said in an interview at the center, which occupies one corner of the Hampshire College campus but is not formally affiliated with the college. “It’s restructuring in a way so we can spend more money on educational programs, a change that’s been in the works for four years and has finally come to fruition.’’

As upsetting as it was to lay off longtime employees, he added, “That happens in the real world when there’s a change in focus. None of these people did anything wrong. Our overhead was too high. They got laid off because the world changes and we have different needs.’’

He pointed to three new job openings the center hopes to fill soon, including a full-time professor of Yiddish studies and communications director to oversee the center’s quarterly magazine, Pakn Treger. Two more vacancies resulting from voluntary retirements have left a full-time staff of 15, down from a recent high of 22. In addition, five academic fellows fluent in Yiddish are on hand to help design and implement new programs.

However, interviews with several former employees, most of whom would not agree to be quoted by name, paint a less rosy picture of the center’s vitality and future prospects.