하다 / 되다 Valency Pairs: 준비하다 vs 준비되다

You already know that 하다 bolts onto a noun to build a verb: 준비 (preparation) + 하다 → 준비하다 (to prepare something). Here is the sequel that doubles the payoff. For a large class of Sino-Korean nouns, you can swap 하다 for 되다 and get a second, ready-made verb that means "become X-ed" — 준비되다 (to be/get prepared). One noun, two off-the-shelf verbs: an active one and a result one. This is one of the most useful patterns in intermediate Korean, and it lets you sidestep the full passive machinery for a huge chunk of the vocabulary.

The core swap: 하다 acts, 되다 results

Take any of these Sino-Korean action nouns and you get a matched pair. The 하다 verb is transitive — it takes an object and names someone doing the action. The 되다 verb is intransitive — no agent in sight, it just presents the result as something that happens or is now the case.

The cleanest way to feel the contrast is a minimal pair. Same event, two viewpoints:

Notice what changed. In the 하다 sentence, I am the nominative subject and 회의 wears the object particle 를. In the 되다 sentence, 회의 has been promoted to the nominative subject with 가, and the person who did the preparing has simply disappeared. That disappearing act is the whole point of 되다: it removes the agent and lets you present a result as though it arose on its own.

Why English speakers need to re-file this

In English, "prepare" and "be prepared" are the same verb in two voices — active and passive. You conjugate one lemma. Korean, for these compound nouns, hands you two separate dictionary words. You are not passivizing 준비하다 to get 준비되다; you are picking a different verb off the shelf. That reframing matters because it stops you from trying to build the result form and lets you just reach for it.

Each of those would be clumsy with the 하다 verb, because there is no salient agent — the movie starts, vacation begins, the class was cancelled (by nobody you're naming). English reaches for the passive or an intransitive "start"; Korean reaches for 되다.

And when there is an agent you want to foreground, you use 하다:

The 걱정 pair: an emotional twist

걱정하다 / 걱정되다 deserves its own look because the emotional vocabulary works slightly differently from the neutral ones, and it's extremely common in daily speech. 걱정하다 means "to worry about (something)" — you are the worrier and the thing worried-about takes 을/를. 걱정되다 flips it: the thing becomes the grammatical subject with 이/가, and the sentence reads "X is worrying (to me) / X weighs on me." No one is being blamed for worrying; the worry just arises.

This 되다 pattern — "X 이/가 걱정되다" — is how Koreans most naturally say "I'm worried about X." It feels less accusatory and more like a state that comes over you, which is exactly the middle-voice flavor 되다 specializes in. The same shape drives 기대되다 (to be looking forward — lit. "it excites anticipation in me") and 긴장되다 (to feel nervous).

This is the lexical route — not the whole passive story

Korean has a fuller passive system: a set of fused suffixes 이/히/리/기 (잡다 → 잡히다 "be caught," 열다 → 열리다 "be opened") and the productive -아/어지다 ending. The 하다/되다 swap on this page is a third, simpler route that exists only for 하다-nouns — and where it exists, it's the natural choice. You don't say ×준비히다 or bolt a passive onto 준비하다; the ready-made 준비되다 is already sitting there. Think of 되다 here as the resultative partner Korean pre-installs for every 하다-noun, so you rarely have to reach for the suffixes with this vocabulary at all. The full 이/히/리/기 passive, the causative machinery, and where 되다 sits among them are laid out in the passive overview and the 하다 / 되다 / 시키다 triplet.

Common Mistakes

1. Bolting a passive onto 되다. 되다 is already the result form — you never add another passive on top of it. Learners who don't trust the ready-made verb produce a double passive.

2. Giving the intransitive 되다 verb an object. 시작되다 / 준비되다 take a subject (이/가), never an object (을/를). If you have an agent acting on an object, you need the 하다 verb.

3. Using 하다 where the result reading is meant. If the subject isn't doing anything — it's just ending up in a state — 하다 sounds like the subject performed the action on itself.

4. Spelling 됐 as ×됬. 되었어요 contracts to 됐어요, not ×됬어요 — the vowel is ㅙ (되 + 었 → 됐). This is one of the most common native typos too; the full 되 vs 돼 rule lives on 되다 vs 돼요 spelling.

Key Takeaways

• A Sino-Korean noun gives you a built-in voice pair: 하다 = active ("do X," takes 을/를), 되다 = result ("become X-ed," takes 이/가).
• 되다 removes the agent and promotes the thing to subject — a ready-made middle/passive without any 이/히/리/기 suffix.
• English uses the active vs passive of one verb; Korean gives you two distinct lexical verbs — so reach for 준비되다, don't build it.
• Never stack a passive on 되다 (×준비되어지다), never give 되다 an object (×회의를 시작됐어요), and don't use 하다 for an agentless result (×문제가 해결했어요).