Kids are so innocent

I met the little girl at the waddling pool while I was there with the kids. Paula was 4, German, and speaks fluent English. She seemed to enjoy playing with Adik a lot, insisting that I put Adik on her little lap or holding Adik in the water. She traced Adik’s hand and asked, “Why is the baby so brown?”
“Well,” I attempt to answer a question I’ve never been asked before, “We live in a tropical climate here, where it’s good for us to have this colour.”
“But why is the palm white? Why is it different?”
“Hmm.. that’s because the cells making up this part and that part are different,” another feeble attempt.

At one point, when Along was talking to Paula, she asked me, “Why isn’t he speaking properly?”
“He is speaking properly. It’s just that my son speaks Malay, because that’s our first language. I haven’t taught him English yet.”

Paula was a curious girl and she spoke her mind.
“Is that your swimming costume?” Paula asked.
I wanted to say that I can’t really swim, so technically it’s not my swimming costume, but of course that’s not what she meant.
“Yes, it is. Do you like it?” I asked back.
“It’s too.. different.”
“Well, I like to keep covered.”

I was quite surprised when Paula asked, “What does oh-la-la means? Your son keeps saying it.” I thought that oh-la-la is universally understood.
I wasn’t quite sure myself, but I attempt anyway. “Oh-la-la is just syllables we use to sing a note, and an expression to say that’s it’s wonderful and great.”

As I watched the kid in the pools played together: Along, Paula, and the locals in their transparent underwears, jumping in circles, chanting “Oh-la-la, oh-la-la!” I thought - kids are just so innocent. Paula noticed differences, and asked out of pure curiousity. She had no prejudice or suspicions. When and how do we teach our kids about other people being ‘the others’? When differences separates us and them?