Heading out on a nature walk near their Carbondale, Colorado, home, Rachel Mulry and her three kids review some words: verde (green), naranja (orange), rojo (red). The family is learning Spanish ...

I still remember my introduction to Spanish as spoken in rural Costa Rica. I had a good, but inflexible vocabulary, with one word in Spanish for most nouns and verbs. Cerdo was the word for pig, until ...