Where you are from

Many older country names end in 국 (guk), a syllable from Chinese meaning country: 영국, 미국, and 한국 (hanguk), Korea itself. These names were fixed long ago, when Korea took them from Chinese writing, so they rarely resemble the English. Countries that entered everyday Korean more recently are borrowed by sound instead, like 캐나다, and those are easy to guess. So if a country name looks nothing like the English, it is probably an old Chinese-character name, and it simply has to be learned.

Where English has a set of irregular adjectives, British, French, Dutch, Korean uses one noun pattern: country, then 사람. Because the whole phrase ends in 사람, it always takes 이에요, whatever the country, so there is only one shape to learn. The question 어느 나라 사람이에요? mirrors the answer word for word, with 어느 나라 sitting where the country will go. That habit, a question built in the exact shape of its answer, is the same one you saw with 이름이 뭐예요? on day 2.

은/는 marks the topic: the thing the rest of the sentence is about, close to 'as for' in English. It follows the same rule as day 2's 이에요 and 예요: 는 after a vowel, 은 after a consonant. The ㅇ at the start of 은 is silent, a placeholder that lets the consonant before it slide across, which is why 이름은 sounds like i-reu-meun. 도 sits in the same slot and replaces 는 because the two do the same kind of job, telling the listener how this item relates to others: 는 says 'this one, as the topic', and 도 says 'this one, as well'.