An open letter to African-American kids. The other day, I used a big word in this column. The word was brobdingnagian; it’s from a book called “Gulliver’s Travels” by Jonathan Swift, a fantasy about a man whose adventures take him to a number of strange lands. One of those lands was Brobdingnag, where the people were all giants. Thus, “brobdingnagian” is a big word that means, well … big. (I like using it because it’s odd and kind of ugly-sounding.)

Anyway, some guy e-mailed me about it. Here’s what he said:

“Uncle Tom:

Stop trying to act like the white man and mastering his culture. … I mean, bro, your using white man words like Brobdingnabian or whatever. I never hear talk like that on BET. For us homeys, keep it real. If you want to describe something as big, say ‘Shaq-size.”‘

My middle son thought it had to be somebody’s idea of a joke. And it might be. But there are some rather … odd people out there, so I’m not sure. Not that it matters. Whether it was meant as a joke or not, it made me laugh out loud.

Then I thought about you.

It occurred to me: You hear stuff like that all the time, don’t you? Seems like everybody has an idea of what you can and cannot do, who you can and cannot be friends with, how you ought and ought not speak, where you can and cannot go, if you want to “keep it real.” If you want, in other words, to be considered truly black.

I’ve heard the story a hundred times, guys. I’ve heard it from your teachers, heard it from my own kids, even heard it from some of you. Like a girl I knew who said black kids ostracized her because she spoke standard English and liked a white boy band.

You know the crazy part? When white people prejudge us, when they say blacks can’t do this, that or the other, when they demand that we conform to their expectations of what black is, we have no problem calling them on it. But when black people do the same thing, we’re more apt to soul search about why we don’t fit in.

You have to wonder at that. Should it really matter whether it’s a white person or a black one who presumes us to be less than we are? Doesn’t the presumption stink either way?

I’m going to tell you something you might not want to hear. If you have a goal in this life, something you want to be, you have to realize that the road between here and there might get narrow sometimes. There may be parts you have to walk alone because there’s no space for all your friends; there’s only room for one.

Maybe you enjoy opera, maybe you want to be an astronaut, maybe you’d like to be a surgeon. And maybe some black people tell you “we” don’t do those kinds of things.

They’ll say they’re keeping it real, but the only thing they’re keeping is some old lies that date all the way back to slavery. White people — many, not all — have told us those lies every day for four centuries, told them so constantly and so convincingly that some of us can’t help but to believe.

So when black people repeat those lies, when they advise you to dream the kind of dreams black kids are supposed to dream — rap star, basketball player, pimp — you have to recognize it for what it is. You have to know that Marian Anderson sang opera, Dr. Mae Jemison went into space on a shuttle, Dr. Daniel Hale Williams performed the first successful surgery on a human heart and all three were black, like you.

Most of all, you have to be prepared, if need be, to walk that road alone.

I won’t lie: it’s not easy. People — black and white — will always have expectations and when you refuse to live by those expectations, they’ll call you names, they’ll shut you out. It’s not easy, but I guarantee that if you stay with it, you’ll find that it is worthwhile.

I guess what I’m telling you is this: Please have the guts to be who you are. And to dream brogdingnagian dreams.

Leonard Pitts Jr., winner of the 2004 Pulitzer Prize for commentary, is a columnist for the Miami Herald.