Learn Hardcore Korean: gageeseo sejereul sayo. - I buy detergent at the store.

가게 means store, and the particle -에서 marks the location where an action takes place. Together 가게에서 means at the store. While -에 can indicate a static location or destination (“to the store” or “at the store” as a point), -에서 specifically signals the place of an action (in this case, buying).

Why is the subject omitted in 가게에서 세제를 사요, and who is buying the detergent?

Korean often drops the subject when it’s clear from context. Here, the implied subject is 저 (I) or 우리 (we) depending on who’s speaking. The polite ending -요 in 사요 hints that it’s a first-person statement, so the sentence means I buy detergent at the store.

What role does -를 play in 세제를 사요?

The particle -를 marks the direct object of the verb. 세제 means detergent, so 세제를 shows that detergent is what’s being bought. Without -를, you wouldn’t know what the verb 사다 (“to buy”) is acting upon.

Why is the verb placed at the end, and what does -요 indicate in 사요?

Korean follows a Subject-Object-Verb (SOV) order, so the verb always comes last. 사요 is the present-tense polite form of 사다 (“to buy”). The ending -요 makes the sentence polite and appropriate for everyday conversation with strangers or acquaintances.

How would you express the same idea in a more formal register?

Use the formal polite ending -ㅂ니다 instead of -요. Change 사요 to 삽니다, giving 가게에서 세제를 삽니다, which is suitable for official announcements or formal presentations.

Is it possible to drop particles in casual speech and say 가게에서 세제 사요?

In very casual spoken Korean, some speakers omit particles for brevity, resulting in 가게에서 세제 사요. However, this is colloquial and can cause ambiguity. In standard or written Korean, it’s better to include -에서 and -를.

How can you change 가게에서 세제를 사요 to past or future tense?

For past tense, replace 사요 with 샀어요:
가게에서 세제를 샀어요. (I bought detergent at the store.)
For future tense, use -을 거예요:
가게에서 세제를 살 거예요. (I will buy detergent at the store.)

Can you switch 가게에서 and 세제를 in the sentence without changing the meaning?

Yes. As long as each word keeps its particle and the verb stays last, you can say either:
가게에서 세제를 사요.
세제를 가게에서 사요.
Both mean I buy detergent at the store, though starting with 가게에서 often sounds more natural when emphasizing the location.

How would you ask Where do you buy detergent? using this structure?

Insert 어디에서 (where + location particle) before the verb:
세제를 어디에서 사요?
or
어디에서 세제를 사요?
Both literally mean “At where do you buy detergent?” and are common ways to ask that question.