The other day I visited Sophie’s classroom. That’s not so unusual (though I’ve not been as good about it this year, I must admit). But I was halfway to the parking lot afterward when I realized that for the first time ever, my daughter didn’t sob when I left. It’s been a not-so-nice byproduct of classroom volunteering. Sophie doesn’t usually get upset when I leave her in other situations (though she’s not always thrilled) but once I’m actually inside the school, she can’t stand the thought of separation.

Not this day. This day she gave me a hug and a cheerful wave. It’s not just that she’s growing up. She had her BFF by her side.

Of all the friendships fostered in 2010 in our household — and there have been many — the most special is the one we’re developing with Sarah and her family.

I’ve written about her before: Sarah and Sophie hooked up in kindergarten. Ms. X noticed early on that the two were pals, she thought it was perfect — explained that Sarah’s the youngest of four and was obviously welcoming the idea of a friend who might need a bit of big sister-ing.

“Oh, and you’ll really like the mom,” she said. “She’s very cool.”

An understatement. Rachel is a class act. Funny, smart — and so kind. I know myself too well. If Sophie had never come around and a kid with special needs had turned up in one of my kids’ classes, I know exactly what I would have done. The same thing I did my whole life when I saw a bagger at Safeway with obvious developmental disabilities. Looked the other way.

But not Rachel. She approached me at Sophie’s sixth birthday party, asking if we could arrange a play date. And not Sarah. She still watches out for Sophie, but over the last two and a half years they’ve developed a deep friendship; it’s incredible to watch.

I suppose it’s not unlike the story I’m working on at the moment (well, for the last few months — it’s slow going) about Spanish immersion programs.

Stick your kindergartener in a classroom where the teacher speaks only Spanish, and the kid will (eventually) emerge fluent. Their brains are sponges at that age, they really do soak it up. I’m seeing it in action. I think it’s the same, in a way, with Sophie. No, not every kid soaks her up — not by a long shot. Ditto for the parents, and I certainly can’t blame them. But a few kids, yes. They don’t see the differences, they’re not resistant to learning. They’re not afraid, like I am, to learn a new language.

I’m watching that at home, too. The other day, Sophie was asleep in my bed, and Annabelle quietly crawled in for a Sunday morning cuddle. I dozed off myself, then rolled over and watched Annabelle. She was propped on an elbow, running her sister’s hair through her fingers as gently as anything I’ve ever seen, gazing at her face. Sure, she gets as frustrated with Sophie as anyone. But I think she loves her in a way you can only love someone you’ve grown up with, side by side.

I watched Annabelle watching Sophie, and wondered just what she saw.