My son Sam is five months old. He does not laugh.

Believe it or not, there are those who would take this to mean that he's miles behind in his language development. Most kids readily laugh by four months, and many (including Sam's older brother Max) do it even earlier.

Is our doctor concerned? Hardly. Sam may not laugh much (if you tickle him really hard on his upper chest--and his shirt is dry rather than soaked with drool--he might deign to deliver a couple guffaws), but he smiles all the time and makes much more noise than the average kid his age. Turn out that most of the books are a wee bit wrong: laughing isn't a developmental stage per se. Neither is crawling, actually. I never crawled as a child, and my motor skills aren't that much worse than those of the average person.

In any case, Sam does "talk" in the way infants talk. A couple months ago he began making the kinda groaning vowel sounds that very young children make. These noises aren't speech, and they doesn't sound exactly human, but there is a definite mammalian ring to them. Think grizzly bear on seconal. Or hound dog on LSD. Take your pick.

Last week, Sam decided that his first language wasn't good enough for him. So he took off in an entirely different direction. Now he sounds like the bird house. Not any one bird, mind you, the entire bird house. At a good zoo, one with dozens of species flying around. He makes these high-pitched squealing noises that sound like a hawk just before it's ready to pounce on a meal. He pumps out these complicated warbles that sound like the love song of a lisping toucan. He wrings some of the most exquisite bird calls out of his developing voice box. And then, when he feels good, he starts combining them, sometimes going on for almost an hour.

Not many folks have experienced one of Sam's concerts. We had some friends over this evening, and Sam obstinately refused to make any noise whatsoever. I described these noises to our friends (parents of one with another on the way), and they nodded politely the way parents do when they think their pals are exaggerating about their "brilliant" children. I didn't blame them. I wouldn't have believed it either. And then, five minutes before they left, he began.

It wasn't his best performance. He threw in a couple of hawk calls and let loose then this really cool thing where he makes one noise while breathing in and another while breathing out. I don't understand how he does that, since Sam breathes exclusively through his nose. But maybe his sinus passages are contributing some sort of resonance to the effect or something. Hard to say.

In any case, even this relatively meager performance unsettled our friends. Sam really does have the ability to transform our home into some sort of bird house simulation. What's nice about it is that Sam only makes these noises when he's happy. His unhappy noises are much more normal: A throaty whine and a fine collection of cries. So when Sam goes all avian on me, I'm happy just to listen. Most of the time, I can't watch him while he's singing; it's just too weird to think that these loud, powerful noises are emanating from a little guy who's barely two feet tall. Every once in a while I do glance over, and the look on his face seems to belie that he, too, is pretty damned impressed with what's coming out of his mouth.

All kids are different. By and large, Sam and Max are polar opposites. While they do share certain pieces of their appearance (they both have blue eyes, for example, though Max's are starting to turn green), their personalities are about as different as can be. Max is intense, temperamental and moody--though, remarkably, still happy most of the time. Sam is scatter-brained, laid back and generally cheerful.

And, you know, he sounds like the bird house.

Jon Worley knows three bird calls--owl, duck and pigeon.