I’ve known him since he was born two years ago, and this weekend, I said to him “Gabe, can I have one marshmallow?” And he toddled over to me and gave me one.

Amazing! Just three months ago all my neighbors’ little boy could do was point to a carton of Tropicana and say “Oh-joo” — that is, orange juice. But now he has language.

Such a miracle it is, really. Remember, running speech doesn’t come across in words nicely separated as they are as I am writing them. He heard: “Gabe — keneyehaavwunmarshmellow?” And hearing that stretch of stuff, he knew just what to do.

Then there’s his sister, about to be five. Watching her learn to talk has been endlessly fascinating to me as a linguist, as when my sister, four years younger, was doing it I was too young too appreciate it. Molly is currently into riddles, but not yet getting their essence. So one of her favorites now goes: “Why do giraffes have long necks? They just do!” (ha ha).

Okay, she’s not ready to write for SNL. But look at that way she uses “just.” Think about it: what does “just” mean in “They just do!” “Simply” — but what does that mean? Not “in a fashion not complex.” “Just” here signifies something more specific: that one classifies the phenomenon in question as having no explanation.

Kids want to know the “why” about everything. Molly is using language at an advanced enough a level to sequester a subset of phenomena that do not submit to “why?,” and has mastered a word that expresses that classification, “just.” We often suppose that kids learn to talk by matching objects and actions to words: doggie, Elmo, eat. But that’s not even the half of it: how many “justs” has Molly seen running around to match a word to?

Language is amazing. My cat understands two words: her name and “no.” Most dogs understand about 20, but “just” is not among them. All day every day people around you are pulling off little marvels of linguistic creativity.

A friend of mine criticized Charles Kimbrough’s recent turn in the Encores! production of “No No Nanette” for not embodying the “cuddly schmendrick” that Jack Gilford did in the 1971 production. That’s perfect, and he said it on the fly. My wife and I got me some Omaha Steaks and she, who doesn’t eat meat, said that it was a trip especially for me as a “meatman.” Not “meat man” with the “man” pronounced in full as in Superman, but pronounced “meatmin,” as we pronounce “policeman,” as if meatman were an established word. But it isn’t; she was playfully making a word on the fly.

People of all walks make art when they talk. Yet the main question we linguists get from the press is “How is the Internet affecting language?” The real answer is: none in particular on how we speak, or write beyond emails.

But even within emails, I delight in what people come up with. A friend just wrote, “OK, so here is a link to a site selling Broadway cast album downloads.” That “OK, so … ” is perfect. It is a written transcription of a spoken way of managing conversational flow: the “OK” indicates acknowledgment of the preceding conversation, and the “so” heralds the new topic.

But in that I had not been engaged in any previous conversation with her, the “OK, so” hearkened to the larger “conversation” we are all engaged in amidst this thing called life. It was a nicely articulate way of introducing the site link in a warm way. Casual, yes — but deftly so.

Her sister, the same day, in response to an invitation: “Much as we’d love to, we’re going out of town. Have fun :).” Some think of emoticons as decadent, but imagine the message without it: the emoticon nicely conveys a jolly, salutory intonation. Without it — “Much as we’d love to, we’re going out of town. Have fun.” — it would seem like the end of a friendship. That emoticon is as articulate as little Molly’s “just.”

Barack and Hillary are given to oral emoticons; specifically, both do a lot of “you know” in their statements. Tuesday night after the primaries, Mr. Obama said: “You know, there is a spirit that brought us here tonight.” Mrs. Clinton on her Kentucky win: “You know, I am so grateful for this victory, and I am so appreciative … “

Call it sloppy, but I call it a new public airing of the warm “I-ness” of what little Molly is doing next door and my pals are doing online. Casual speech is a glorious thing.

Yet so many just hear people around them making mistakes. To linguists, it can seem as if most of the world is colorblind.

Mr. McWhorter is a senior fellow at the Manhattan Institute.