Learn Hardcore Korean: chinguhante badeun pyeonjireul ilgeo. - Read the letter you received from a friend.

한테 is a colloquial dative marker. In the context of 받다 (“to receive”), it marks the giver. So 친구한테 means “from a friend.” You could also use more formal markers like 친구에게 or 친구로부터 without changing the basic meaning.

Why is 받은 placed before 편지, and what form is it?

받은 is the attributive (modifying) form of the verb 받다 (“to receive”). When you want to say “the letter that (I) received,” you turn 받다 into 받은 and put it in front of 편지. Grammatically, this is how Korean builds a relative clause:
– 받다 → 받은 + 편지 = “the received letter” (i.e., “the letter that [I] received”).

Can you break down the phrase 친구한테 받은 편지?

Sure:

친구한테: “from a friend” (giver marked by 한테)
받은: “received” (verb in attributive form)
편지: “letter”
Put together, it literally reads “(the) friend-from received letter,” which maps onto English as “the letter received from a friend.”

Why is there no explicit subject in this sentence?

Korean often omits subjects when they’re clear from context. In this case, 읽어 is an imperative (“read”), so the implied subject is you. The full idea is “[You] read the letter I received from a friend,” but Koreans drop the “you” in everyday speech.

What is the role of 를 in 편지를?

를 is the object particle. It attaches to 편지 to indicate that “the letter” is the direct object of 읽어. Without 를, the sentence would be ungrammatical or ambiguous about what you’re reading.

What tense and sentence type is 읽어, and what level of politeness is it?

읽어 is the informal-low form of the imperative (command) or sometimes plain present in casual speech. Here it functions as a command: “Read (it).” Because there is no honorific or polite ending, it’s only appropriate for close friends, younger people, or situations where informal speech is acceptable.

How would you make this sentence polite or formal?

You have several options depending on the level of politeness:
• Informal-polite (반말 vs. 존댓말 blend): 친구한테 받은 편지를 읽어 줘. (“Read the letter I got from a friend, please.”)
• Standard polite: 친구한테 받은 편지를 읽어요.
• Honorific/polite command: 친구한테 받은 편지를 읽으세요.

Each choice raises the speech level to suit different social contexts.