Learn Hardcore Korean: hoksi tonghwaga an doemyeon mesijiro allyeo jwo. - If the call doesn’t go through, let me know by message.

Korean often drops pronouns when they’re obvious from context. Here, the understood meaning is “If we can’t talk by phone, let me know by message.”
In 알려 줘, the verb 주다 (to give) is a benefactive that implies “to me,” so the recipient is the speaker by default.
You could say 나한테/저한테 메시지로 알려 줘(요) to spell out “to me,” but it’s not required.

What does 혹시 add?

혹시 is a softening hedge meaning “by any chance / just in case.”
It makes the condition feel tentative and the request gentler, similar to English “If by any chance the call doesn’t work, could you…”

Is the sentence polite or casual? What are polite alternatives?

알려 줘 is casual (반말). Use it with friends, younger people, or peers you’re close to.
Politer options:
- 알려 주세요 (standard polite)
- 알려 주시겠어요? / 알려 주실 수 있을까요? (softer, more deferential)
- Very formal: 알려 주십시오
Example: 혹시 통화가 안 되면 메시지로 알려 주세요.

What’s the difference between 통화 and 전화 here?

통화 = the act of speaking on the phone (the conversation/connection).
전화 = the phone/call more generally (device or act of calling).
통화가 안 되다 emphasizes “we can’t get a call connected / we can’t talk.”
전화가 안 되다 can mean “the phone/call won’t work/connect.” In many contexts they overlap, but 통화 sounds more like the voice connection itself.

What exactly does 통화가 안 되면 mean?

Literally, “if the call doesn’t work/connect.”
In everyday terms: “if we can’t get through / if we can’t talk on the phone (for any reason: no signal, busy, call fails, etc.).”

Why not say 통화를 못 하면?

안 되다 focuses on the situation not working or not being possible (connection fails, circumstances prevent it).
못 하다 focuses on the person’s inability to do it (you’re busy, you can’t talk right now).
Both are possible, but:
- 통화가 안 되면 = if the call doesn’t go through/doesn’t work.
- 통화를 못 하면 = if you’re unable to talk (e.g., you’re in a meeting).

What does -면 do in 안 되면?

What does 로 mean in 메시지로? Could I use other words here?

로 marks means/method: 메시지로 = “by message / via message.”
Common substitutes:
- 문자로 (by text/SMS)
- 카톡으로 (via KakaoTalk), DM으로, 이메일로, etc.
메시지 is generic (could be SMS or app); 문자 usually means SMS specifically.

Is 메시지 the correct spelling? I often see 메세지.

Do I need to say 나한테/저한테 before 알려 줘?

Not necessary. The benefactive 주다 implies giving the information to the speaker.
Adding it is fine if you want explicitness: 나한테(저한테) 메시지로 알려 줘(요).

What’s the nuance difference between 알려 주다, 말해 주다, and 연락하다/연락해 주다?

알려 주다: “let (someone) know / inform.” Natural with methods: 메시지로 알려 줘.
말해 주다: “tell (someone).” More about saying the content; less natural with 메시지로 (since 말하다 is “speak”). You’d more likely say 메시지로 보내 줘 or 메시지로 알려 줘.
연락하다/연락해 주다: “contact (me).” Broader; doesn’t specify method unless you add one. Ex: 통화가 안 되면 연락해 줘.

Is 알려 줘 one word or two? I’ve seen 알려줘 too.

Both 알려 줘 and 알려줘 are acceptable. 주다 here is an auxiliary/benefactive; Korean allows either spacing with such auxiliaries.
In texting, the fused form (알려줘) is very common; in careful writing, the spaced form is also frequent.

Why 통화가 and not 통화는?

가 marks the subject in a neutral way: “the call (subject) doesn’t work.”
는 would add a contrast or topical focus: “As for the call, if it doesn’t work, …” Use 는 if you’re contrasting with some other method (e.g., “As for calling, if that doesn’t work, then message me.”).

Can I change the word order? Where can 혹시 go? Do I need a comma?

Flexible options:
- 혹시 통화가 안 되면, 메시지로 알려 줘. (comma optional)
- 통화가 혹시 안 되면 메시지로 알려 줘.
Keep 혹시 near the condition or at the start. Putting 혹시 right before 알려 줘 changes the nuance to hedging the request rather than the condition.

Any pronunciation tips?