CHICAGO — Mary Cate Lynch sat in her mother’s arms before a class of fifth-graders at Oriole Park Elementary School. The 2 1¿2-year-old can’t speak many words yet. But she has mastered a bit of sign language.
“Mary Cate, what’s your favorite sign?” asked her mother.
The blond-haired, blue-eyed child twisted a finger to her cheek and made the sign for — what else? — candy.
That made the fifth-graders in the classroom laugh.
It was a sweet moment of…