MANASSAS, Virginia—Rebecca Apple's Latino students at Osbourn High School call her "Miss Manzana," the Spanish word for "apple." A floating teacher last year, Apple would pile her nine English-Spanish dictionaries and other supplies into a cart and travel down halls thronged with students.

She's one of hundreds of public school teachers in Manassas, in Prince William County outside Washington, D.C., who've struggled to adjust to the arrival of scores of new Hispanic students; a fresh onslaught is expected when school opens in a few weeks' time. Last year, Apple's class size for her beginner English for Speakers of Other Languages course grew so quickly that she was receiving one or two new immigrant students every day for a month.

Matilde Rosa Jimenez