Topic marker: 은/는

We learned about subject marker 이/가 and object marker 을/를. Examples are

1. 제프가 닭볶음을 먹었어요(ate).

Sometimes, we want to emphasize the subject or the object. In such situation, we can use a topic marker, 은 or 는. Like the other markers, "은" comes after words with 받침, "는" comes after words without 받침.

The sentence 1 means Jeff ate 닭볶음. Let's add more to the situation. There were Hyo and Jeff, and they both were supposed to eat 닭볶음, but only Jeff did. Later mom comes and asks if both ate. Then someone who saw that will tell mom

제프는 먹었어요.

This sentence emphasizes that it was Jeff who ate. (not Hyo)

Let's change the situation slightly. There were 닭볶음 and 미역(seaweed)국(soup) to eat. And Jeff only ate 닭볶음, not 미역국. And mom comes later and asks if he ate both. Then she will hear the following answer:

닭볶음은 먹었어요.

Again, it emphasizes that it was 닭볶음 what he ate.

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