Lucky for you, today I'm going to teach you this grammar, and you'll find that it's really not so hard after all!
First off, forget the way this works in whatever language you speak. Because Korean is not English, it's not Spanish, it's not Chinese, etc. Those languages tend to work pretty simply:
First person: I'm going to the store at 3PM.
Direct reported quote: He says, "I'm going to the store at 3PM."
Indirect reported quote: He says he's going to the store at 3PM.
So, so easy. The only thing that changed between the direct and indirect quotes is the pronoun and the conjugation of "to be" to match the pronoun ("I am" => "he is"). Who said English is hard? ;)
Korean is a bit more complicated. In Korean, rather than simply changing pronouns, we need to affix a special ending to the verb stem in order to signify that we're reporting speech. This should come as no surprise, because the entirety of Korean grammar is built around verbs and the special endings they get. It's an agglutinative language, after all.
First person: 3시에 가게에 가요. I'm going to the store at 3.
Direct reported quote: "3시에 가게에 가요."라고 (말해)요. He says, "I'm going to the store at 3."
Indirect reported quote: 3시에 가게에 간다고 (말해)요. He says he's going to the store at 3.
Let's take a look at what's going on here. I wrote these in a way that sounds a little bit awkward, but is instructive.
Direct reported quote:
The direct reported quote is easy, and is very similar to English (which is why many English speakers use this form all the time, even when the indirect is more appropriate). It's used for reporting exactly verbatim what somebody else said. We put quotes around what the person said, and then we affix "라고" to the quote, and then add "he says", "she says", etc to finish off the sentence. Note that I put parentheses around 말해. The reason is that one or both are often left out. Just -라고 하다 literally means "does say so-and-so", so something like "3시에 가게에 가요"라고 해요 means "He says, 'I'm going to the store at 3.'" But Koreans like shortening things if they can, and since the -라고 is the important part in the construction, it's perfectly legitimate to leave off the "saying" verb completely:
Polite: "3시에 가게에 가요"라고요. He says, "I'm going to the store at 3."
Casual: "3시에 가게에 가요"라고. He says, "I'm going to the store at 3."
Indirect reported speech:
The direct quote was simple, but not nearly as useful as indirect reported speech. We almost never quote people directly unless we're acting out something that happened. We're often just naturally saying something like, "He said he's gonna be late." So, how do we form the indirect reported speech? Simply find the verb stem, add -ㄴ다고/-는다고 for verbs (no 받침: -ㄴ다고, 받침: -는다고), -다고 for adjectives (and 있다/없다, which often behave like adjectives), and -라고/-이라고 for nouns. Some examples will make this more apparent.
친구가 오후에 도서관에 간다고 해요. My friend says in the afternoon he's going to the library. Since the verb is 가다, the stem is 가, so we add -ㄴ다고 to get 간다고, and we're good to go.
Quick note on Korean grammar versus English grammar: While "says going" is totally not a valid sentence in English, "간다고" is a completely proper sentence in Korean. The only thing a Korean sentence needs to be complete is a verb. And the ending of the verb tells you how the verb is behaving. So:
간다고. I said I'm going.
간다고. He says he's going.
간다고? Did you say you're going?
간다고? Did you say he's going?
간다고? Did he say he's going?
OMG, how do I know who said what? Well, obviously we need context to understand which meaning is correct, but this is the beauty of Korean - you can express a complete, meaningful statement in one word!
Here's one with an adjective:
선생님이 숙제는 진짜 중요하다고 하셨어요. Teacher said as for homework, it's really important. (i.e., "Teacher said that homework is really important.")
Since 중요하다 is an adjective, when we strip off the -다 to get the stem, we simply add -다고 to make it into reported speech. Also, note that for the actual "speech" verb, we match the tense with the speaker. Since 선생님 is an honorific, we use "하셨어요". Note that we do not have to match the other verb with the subject, i.e.,
And again, we can remove everything but the verb to form a totally valid sentence:
중요하다고! He says it's important!
And now one with a noun:
학생이라고 해요. She says she's a student.
As for the final verb, so far we've been using 말하다 (says), 하다 as an abbreviation for 말하다, or leaving it out completely since the reported speech is clear from the 다고/라고 part. But if you like flourish, you can change the final verb to any speech-related action, like "shouts", "yells", "whispers", etc.
그 여자를 많이 사랑한다고 고백했다. He confessed that he really loves that girl.
In this example, we also show how the final speech verb can indicate the tense of the actual speech that has taken place. That is, 고백했다 is in the past tense, emphasizing that he "confessed" rather than "confesses". The tense of the final speech verb can be whatever you want, e.g., "사랑한다고 고백해야겠다" (I really need to confess that I love her), "사랑한다고 고백하면 ..." (If I confess that I love her ...), "사랑한다고 고백할게" (I will confess that I love her), "사랑한다고 고백했을 때 ..." (When I confessed that I love her ...), etc. The possibilities are endless.
The reported speech verb can also take on a tense:
늦게 온다고. He says he's coming late.
늦게 올 거라고. He says he will come late.
늦게 왔다고. He says he came late.
Combining, both the reported speech verb and the final speech verb can take on tenses:
늦게 온다고 했어. He said he's coming late.
늦게 온다고 (해). He says he's coming late.
늦게 왔다고 (해). He says he came late.
늦게 왔다고 했어. He said he came late.
All slightly different nuances, but constructions we use in English all the time.
So, why is this so useful? Well, as a learner of a foreign language, unless you've got magical powers, you probably are not always 100% sure of what people are saying to you. With the indirect reported speech form, you can now confirm what people are saying by asking, "Are you saying X"?
가: 이게 뭐냐? 진짜 맛없다. WTF is this? It tastes really nasty.
나: 뭐라고? 맛없다고? What'd you say? Are you saying it doesn't taste good?
How incredibly useful is this?? First off, "뭐라고?" is now possibly your most useful Korean phrase. It literally means "What is/was said?", so if you say it to someone who just said something to you, it means "What did you say?". It's casual, of course, so be careful, but you can make it more polite by adding a 요: 뭐라고요? Or with the honorific, 뭐라고 하셨어요? So useful. But be careful with tone of voice, because it can easily be misconstrued as argumentative, as in, "What'd you say??"
The second sentence of the reply, 맛없다고?, is asking if the first person said what you think they said. Note that this is more natural than just asking directly "맛없어?", which means, "Is it not delicious?", which is a weird thing to ask when that's what they just told you.
And of course, other than simply confirming what you think people said to you, you can now begin to talk about what other people said. Time to gossip away!
Next time: Reporting on questions, commands, and suggestions. Plus more abbreviations. In the meantime, the best way to practice this amazingly useful verb form is to start confirming what Korean people say to you. And, you know, gossip about what people said, if that's your thing. :)