Learn Hardcore Korean: biga geuchyeoseo dahaengiya, ije chulbalhaja. - I’m glad the rain stopped; let’s leave now.

-가 marks the grammatical subject: “the rain (is the thing that) …”
-은/는 topicalizes: “as for the rain, …”
Here, 비가 is the neutral choice to state the fact that the rain stopped. Using 비는 would sound like you’re contrasting rain with something else or continuing a previous topic. It’s possible but adds a contrast/topic nuance: 비는 그쳐서 다행이야 (“As for the rain, it stopped, so that’s a relief.”).

Why is it 그쳐서 and not 그치어서?

The verb is 그치다 (“to stop/cease”). When you add the connective -어서, you get 그치어서, which contracts to 그쳐서 (이 + 어 → 여). So:

그치다 + 어서 → 그치어서 → 그쳐서. Pronunciation: geu-chyeo-seo.

What does -아서/어서 express here—cause or sequence?

Cause/reason. 비가 그쳐서 다행이야 means “Since the rain stopped, it’s a relief.” With evaluations/feelings (다행이다, 좋다, 아쉽다, 미안하다, etc.), -아서/어서 commonly marks the reason.

How is -아서/어서 different from -니까 here?

-아서/어서 sounds like a natural, matter-of-fact reason leading to a personal evaluation: “(Because it stopped) it’s a relief.”
-니까 often feels like “since/now that,” and is especially natural when the main clause is a suggestion or command: 비가 그치니까(요) 이제 출발하자/출발하세요.
You can say both: 비가 그쳐서 다행이야 (evaluation) vs 비가 그치니까 이제 출발하자 (proposal).

Can I say “비가 그쳐서 이제 출발하자” as one sentence?

In standard grammar, it’s awkward. -아서/어서 isn’t normally used to give a reason for an imperative or proposal in the same sentence. Better:

Split it: 비가 그쳐서 다행이야. 이제 출발하자.
Or use -니까: 비가 그치니까 이제 출발하자.

What exactly is 다행이다?

다행 is a noun meaning “relief, good fortune.”
이다 is the copula “to be.”
다행이다 literally means “(It) is a relief.”
Informal: 다행이야; polite: 다행이에요; formal: 다행입니다.

Why not say 다행해?

Because 다행 is a noun, not a verb/adjective you can conjugate with 하다 in this meaning. You say 다행이다 (“it’s a relief”), not 다행하다. For the adverb “fortunately,” use 다행히(도).

What’s the difference between 다행이야, 다행이에요, and 다행입니다?

다행이야: casual, to friends/peers.
다행이에요: polite, everyday speech.
다행입니다: formal/deferential (announcements, customer service, talking to superiors).

How can I make the whole sentence polite?

A few natural options:

비가 그쳐서 다행이에요. 이제 출발해요.
비가 그치니까 이제 출발할까요? (suggestion)
More formal: 비가 그쳐서 다행입니다. 이제 출발하시죠.

What nuance does 이제 add compared to 지금?

이제 = “now (that circumstances have changed), from now/at this point.” It signals a transition (rain stopped → time to go).
지금 = “right now (this moment),” more purely temporal.
Both can work, but 이제 출발하자 highlights the shift after the rain stopping.

Is 출발하자 the same as 가자?

출발하자 = “let’s depart/set off” (start a journey/schedule).
가자 = “let’s go” (more general). In many contexts either is fine, but 출발하자 sounds a bit more like beginning a planned departure. Alternatives: 떠나자 (“let’s leave”), 이제 가자 (“let’s go now”).

Can I say 비가 멈췄다 instead of 비가 그쳤다?

Yes, people do say it and it’s understood. Nuance:

그치다 is the most idiomatic for precipitation/noise/crying stopping.
멈추다 is “to stop/come to a halt” for motions/actions and can be used for rain colloquially, but 비가 그치다 is the default.

Can I drop -서 and say 비가 그쳐 다행이야?

In casual speech, yes—you’ll hear 그쳐 다행이야. In writing or careful speech, keep -서: 그쳐서.

Could I use the topic marker and say 비는 그쳐서 다행이야?

Grammatically fine, but it topicalizes/contrasts “the rain.” Use it if you’re contrasting with something else (e.g., “The rain stopped, but the wind hasn’t”). Neutral statement → 비가 그쳐서 다행이야.

Why is there a comma—are these two sentences?

They’re two independent clauses placed side by side:

Clause 1: 비가 그쳐서 다행이야 (evaluation)
Clause 2: 이제 출발하자 (proposal) You could also make them two sentences with a period. The comma is a stylistic choice for flow.

Can I say 출발하자요 to be polite?

Not in standard Korean. -자 (let’s) is inherently informal and doesn’t take -요. Use:

출발할까요? (Shall we depart?)
출발해요. (Let’s depart.)
출발하시죠. (Let’s depart—polite/assertive.)