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David and Paige introduce you to the superhero of the punctuation world: the comma! Practice this yourself on Khan Academy right now:

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"Today we're going to talk about using commas in dialogue," said David and Paige, KA's resident grammarians.

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- [Voiceover] Hello grammarians, hello Paige. - [Voiceover] Hi, David. - [Voiceover] So, today we're gonna learn about hyphens. And what a hyphen is, it's a little stick, like this, as opposed to a dash, which is about twice as long. And people confuse them a lot, but they have very different functions. So what a hyphen is used to do is it's used to join two words into one. - [Voiceover] All right. - [Voiceover] So, for example, we have the word yellow. That's a word with meaning. We have the word green. That's a word with meaning. - [Voiceover] Yes. - [Voiceover] And we may have a word that does fit right in between those two or two at once, like chartreuse or whatever. - [Voiceover] Okay. - [Voiceover] You know, but not everybody wants to use the word chartreuse. - [Voiceover] No, it's kinda crazy. - [Voiceover] Kind of a wacky word. So, instead of doing that, you might just wanna say yellow-green, and connect yellow and green with a hyphen. So yeah, so a hyphen is joining these two things. But let's say we had a sentence like, "Her hair was yellow -- green were her eyes." You know, and so we're still separating the words yellow and green with a stick, but a dash is longer, and instead of uniting yellow-green, it's separating them the way that you know, a semicolon might. - [Voiceover] Yeah, it's not one thing, it's she has yellow hair and green eyes. - [Voiceover] If she had yellow-green hair, that would be a different story. - [Voiceover] Yes. - [Voiceover] So what's neat about hyphens and what's kinda confusing about hyphens is that whether or not we use a hyphen indicates how common a compound phrase is. So, Brian Gardner in Gardner's Modern American Usage, and in the Chicago Manual of Style draws this distinction with compound words. And I should first say what a compound word is, right? A compound word is two words smacked together somehow, right? So, if we take the... so once upon a time, at the dawn of the Internet page, - [Voiceover] Okay. - [Voiceover] when dinosaurs walked the Earth, and I was just a wee little baby, - [Voiceover] Yes. - [Voiceover] you would refer to getting on line, right. And then, as it became more and more prominent, and more and more popular, this is what's called an open compound, then it became on-line, separated with a hyphen. This is what's called a hyphenated compound. - [Voiceover] Makes sense. - [Voiceover] And now, when we think about it, it's just an adjective, and it's online, and this is a closed compound. - [Voiceover] Right, okay. It became closed, cause everyone knows what that means. - [Voiceover] Right, so you would use hyphenated compounds when you're kind of in this intermediary stage of acceptedness. - [Voiceover] So like, maybe one day, in the future, yellow-green will be a super common color. Right, it's everyone's favorite color, so it'll just be smushed together with no hyphen. - [Voiceover] Today is not that day. - [Voiceover] Today is not that day, so there's a hyphen there. - [Voiceover] Right, I think it's also important to hyphenate for clarity. Let me explain what I mean by that. - [Voiceover] Yeah. - [Voiceover] So, first of all, when I say hyphenate, that's just a word that means to put a hyphen in something. - [Voiceover] Yes. - [voiceover] To hyphenify. So if a compound word could be misconstrued or misunderstood, you just throw in a hyphen or check a dictionary or a style guide. So, okay, so, Paige. - [Voiceover] Yes. - [Voiceover] I would like to raise some chickens. - [Voiceover] Good idea. - [Voiceover] So, in order to raise some chickens, I need a chicken coop, right. - [Voiceover] That is, yeah, true. - [Voiceover] And a coop, right, C-O-O-P, is a place where chickens live. It's like a little enclosure. - [Voiceover] Yeah. - [Voiceover] But let's say I wanna buy this coop from a community-run business, right, what's called a cooperative business, or a co-op. Well, now sometimes it appears like that. Like that, like C-O-O-P, but if I said something like, "I wanna by my coop from the co-op," like that, it'll end up looking like this. - [Voiceover] I wanna buy my coop from the coop. - [Voiceover] Right. - [Voiceover] Or my co-op from the co-op, or co-op from the coop, or something. - [Voiceover] So, in order to be clear, it really helps to put in that little hyphen. And that's the difference, right. So you're using this to say, oh, you know, this is actually short for cooperative, you know, cause it's operated by a bunch of people working together, as opposed to this word, which is just C-O-O-P. - [Voiceover] Right. - [voiceover] So you wanna hyphenate for clarity when you can. - [Voiceover] Makes sense. - [Voiceover] So let's bring all this together, right. So I made a yellow-green coop with the co-op. - [Voiceover] Okay, you all worked together to make a yellow-green coop. That's pretty cool. - [Voiceover] So we're connecting yellow and green with a hyphen. We're connecting co-op with a hyphen to differentiate it from this word coop. And that's basically what you use hyphens for. You can learn anything, David out. - [Voiceover] Paige out.

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Voiceover] Hello grammarians, hello Paige. - [Voiceover] Hi, David. - [Voiceover] So, today we're gonna learn about hyphens. And what a hyphen is, it's a little stick, like this, as opposed to a dash, which is about twice as long. And people confuse them a lot, but they have very different functions.