Reading a Sentence: Causative or Passive?

Korean builds its passive and its causative with the same four suffixes — 이, 히, 리, 기. The predictable result is that a great many derived verbs are homophones: 보이다 is both "be seen" and "show," 업히다 is both "be carried" and "have carried," 읽히다 is both "be read" and "make read," 안기다 is both "be held" and "hand to." The verb form alone will never tell you which voice is meant. What tells you is the rest of the sentence — how many noun phrases there are and which particles they wear. This page turns that into a reliable reading procedure.

Why the verb can't decide

In a language like English, the two voices look different: "the police caught the thief" (active/causative-flavored) versus "the thief was caught" (passive) use different word shapes and word order. Korean packs both meanings into one derived stem, so a reader can't lean on the verb. Instead, Korean speakers parse the sentence the way you'd read an equation: they identify the subject, count the objects, and interpret the oblique phrases. Once you do that consciously a few times, it becomes automatic. The good news is that the diagnostic is almost mechanical.

The three-step procedure

Step 1 — Find the subject (이/가 or topic 은/는). Is it doing or undergoing? A causative has a causer subject — someone who brings the event about. A passive has a patient subject — the thing the action lands on.

Step 2 — Count the objects (을/를). Is there one? This is the single most decisive clue. A passive has no direct object — the patient has been promoted to subject. A causative typically keeps an object (the thing acted on, or the causee). An extra 을/를 almost always means causative.

Step 3 — Interpret any 에게/한테/에 phrase. The same 에게 shows up in both voices, so it can't decide alone. In a passive it names the agent ("by whom"); in a causative it names the causee ("had whom / to whom"). Let Step 2 break the tie: if there's also an object, the 에게 phrase is a causee and the sentence is causative.

Worked minimal pairs

The cleanest way to feel the procedure is to watch a single verb flip voice as you add or remove an object. Take 씻기다 (from 씻다 "wash"), which is a genuine both-ways homophone.

Nothing about 씻겼어요 changed. What changed is the argument frame: in the first, the child is the subject and there's no object, so it's a passive; in the second, 아이 is now the object (을/를) and 엄마 is a new causer subject, so it's a causative. Now the same test on 업히다 (from 업다 "carry on the back"):

And 읽히다 (from 읽다 "read"):

The classic pair: 보이다

보이다 is the homophone every learner meets first, so it's worth running the procedure on it explicitly. From 보다 ("see"), 보이다 is passive "be visible / can be seen" and causative "show."

Same verb, opposite voices, sorted entirely by Step 2: 바다가 (subject, no object) → passive; 사진을 (object) → causative. And 안기다 (from 안다 "hold/hug") behaves identically:

Look closely at the two 에게 phrases. In 아기가 이모에게 안겼어요, there's no object, so 이모에게 is the agent — the aunt does the holding — and the sentence is passive. In 아이에게 꽃을 안겼어요, there's an object (꽃을), so 아이에게 is the causee and the sentence is causative. The 에게 didn't tell you which; the object did.

The flagship textbook example

The sentence pair most textbooks lead with is worth parsing with the full method, because it shows agent-에게 and causee-에게 side by side.

Run the checklist on the first: subject 도둑이 is undergoing (Step 1 → patient), there's no object (Step 2 → passive), so 경찰에게 must be the agent (Step 3). On the second: subject 엄마가 is doing (Step 1 → causer), there is an object 옷을 (Step 2 → causative), so 아이에게 is the causee (Step 3). The verb 잡혔/입혔 never entered the decision.

Common Mistakes

1. Reflexively reading every 이/히/리/기 verb as a passive. The moment you see an 을/를 object, switch to a causative reading.

The sentence 엄마가 아이를 씻겼어요 tempts a passive gloss — ✗ "Mom got washed by the child." But 아이를 is an object, so it must be causative: ✓ "Mom washed the child." The object is your causative flag; never ignore it.

2. Marking the passive agent with 이/가 instead of 에게/한테. A passive can have only one 이/가 (the patient-subject); the agent takes 에게/한테/에.

3. Marking the causative theme with 이/가. In a causative, the thing acted on is a direct object (을/를), not a subject.

4. Concluding "passive" just because you see 에게. 에게 marks both the passive agent and the causee. Let the object decide.

The sentence 선생님이 학생에게 편지를 읽혔어요 has an object (편지를), so 학생에게 is a causee: ✓ "The teacher had the student read the letter" — not the passive ✗ "The teacher was read a letter by the student."

5. Forgetting that a bare patient-subject with no object is your passive cue. 아기가 안겼어요 has one 이/가 (a patient) and no object, so it's passive ("the baby was held") — not "the baby held (something)."

Key Takeaways

• The suffixes 이/히/리/기 build both voices, so the verb form is never the clue — the argument structure is.
• Count the objects first. An 을/를 object ⇒ causative; a patient-subject with no object ⇒ passive.
• 에게/한테 is ambiguous: the agent of a passive and the causee of a causative both take it. The presence or absence of an object breaks the tie.
• A passive has exactly one 이/가 (the patient-subject); a second 이/가 for the agent is ungrammatical — use 에게/한테/에.
• Practice the procedure on the homophone set — 보이다, 업히다, 읽히다, 안기다, 씻기다 — until reading their voice becomes automatic.