Emily L. Sharp, 68, a retired speech therapist in the Arlington County school system and a noted gardener, died Thursday of a circulatory ailment at Sibley Memorial Hospital.

From 1955 until her retirement in 1973, Mrs. Sharp worked in the Arlington County speech department where she helped pioneer the teaching of English as a second language to foreign-born students.

She was the wife of James R. Sharp, a Washington lawyer.

The Sharps developed extensive azalea gardens at their Arlington home. These gardens have been open to the public during the past several years, with Mrs. Sharp serving as hostess to many public and private garden tours.

Born in Chicago, Mrs. Sharp was a graduate of Northwestern University's School of Speech. She taught school in the Midwest for a number of years in the early 1930s before moving to this area. She also taught for three years in the Prince George's school system during the mid-1930s.

She was a charter member of the Little Falls United Presbyterian Church in Arlington.

In addition to her husband, of the home, she is survived by two daughters, Judy S. Lombardi, of Alameda, Calif., and Susan Swift, of Arlington; a son, James L. of Stockton, Calif., and eight grandchildren.

The family suggests that expressions of sympathy may be in the formed of contributions to the Emily L. Sharp Memorial Fund, Williamsburg Civic Association, 3513 Powtan St., Arlington.