Lazard Seiff, 68, linguist, teacher and retired government aide in employment security, died of cancer Thursday at the National Institutes of Hea lth.

He joined the Labor Department here in 1943, and worked in the employment security field before his retirement in 1973. During that time he spent two years with the State Department's Agency for International Development as a labor adviser to the government of Tunisia.

Mr. Seiff was born in Brockton, Mass. He attended Harvard University and was with the Massachusetts Employment Security Office in Boston before coming to Washington. He was a member of the Coast Guard Reserves in World War II.

A vice president of Temple Beth E1 in Alexandria and a founding member of Temple Rodef Shalom in Falls Church. Mr. Seiff had been a tutor and religioius instructor at both temples for more than 25 years.

He spoke and read Greek, Latin, Hebrew, Yiddish, French and German and taught people for bar and bat mitzvahs.

Mr. Seiff was active in the International Association of Personnel in Employment Security. A master in the American Contract Bridge League, he was a founder of the Labor Department Bridge League.

He is survived by his wife, Beatrice T., of the home in Alexandria; two sons. Herny, of Falls Church, and Jonathan, of Boston, and two grandchildren.

The family suggests that expressions of sympathy may be in the form of contributions to Temple Rodef athy may be in the form of contributions to Temple Rodef Shalom or the American Cancer Society.