The cheerful sign outside Jane Cornell’s summer school classroom in Pennsylvania’s wealthiest county says “Welcome” and “Bienvenidos” in polished handwriting.

Inside, giggling grade-schoolers who mostly come from homes where Spanish is the primary language worked on storytelling with a tale about a crocodile going to the dentist. The children and their classroom at the Mary D. Lang Kindergarten Center, near both mushroom farms and the borough’s bucolic red-brick downtown, are a subtle reminder of America’s changing school demographics. MORE