Why do Koreans say 저는 in one sentence and 제가 in another? And why can 친구가 왔어요 feel different from 친구는 왔어요? In this episode, we break down one of the trickiest parts of Korean grammar: 은/는 and 이/가. Instead of memorizing complicated grammar rules, we'll look at real-life situations and see how changing just one little particle can change the focus, contrast, and nuance of a sentence.