Learn Hardcore Korean: geosire sopawa siktagi isseoyo. - There is a sofa and a dining table in the living room.

에 marks the location where something exists or takes place—similar to “in” or “at” in English. Since you’re saying “(a sofa and a dining table) exist in the living room,” you attach 에 to 거실. (If you were talking about doing an action there, you might use 에서 instead.)

What does 와 do in 소파와 식탁이 있어요? Why not 소파과?

와 is the coordinating conjunction “and” used after a noun ending in a vowel. 소파 ends in ㅏ (a vowel), so you use 와. If a noun ends in a consonant, you’d use 과 (e.g. 책과 연필).

Why isn’t there a plural marker (like -들) on 소파 and 식탁, even though there are two items?

Korean usually drops explicit plural markers when the context already makes plurality clear. Saying 소파와 식탁 naturally implies two distinct items. Adding -들 here would be redundant and is rarely done.

Why is 이 attached to 식탁?

이 is the subject particle used after a noun ending in a consonant. Since 식탁 ends in ㄱ (a consonant), you attach 이 to mark it as the subject of 있어요. If the noun ended in a vowel, you’d use 가 instead.

Can I say 소파하고 식탁이 있어요 instead of 소파와 식탁이 있어요?

Yes. -하고 is a more casual way to say “and,” and it works after both consonants and vowels. 소파하고 식탁이 있어요 sounds friendly and informal. It’s perfectly fine in spoken Korean, though you’ll see 와/과 more often in writing or slightly more polite speech.

What’s the nuance of 있어요, and can it be replaced with 있습니다 or 있다?

있어요 is the polite-informal form of 있다 (“to exist,” “to have”).

있습니다 is the polite-formal version (used in speeches, announcements, business contexts).
있다 by itself is the dictionary/plain form (used in writing/dictionaries or among very close friends in casual speech).

How do I know whether 있다 means “to exist” or “to have”?

Context and particles guide you. With -에 after a place, you’re describing existence (“there is/are”). Without a place marker but with a person/topic marked by 은/는, it often means possession (“I have…”). For example:
• 내 책상이 있어요 (with 에 omitted after “책상”) tends to mean “I have a desk.”
• 책상이 방에 있어요 (with 에 on “방”) means “The desk is in the room.”

Can I change the word order to 소파와 식탁이 거실에 있어요? Would it sound different?

Yes. Korean word order is relatively flexible because particles show each word’s role. 소파와 식탁이 거실에 있어요 is equally correct and perhaps even more natural in neutral speech, since subject–location–verb/order mirrors the typical SOV pattern. The original order just puts emphasis on the location first.

What’s the difference between 와/과, 하고, and (이)랑 when saying “and”?

• 와/과: more formal; 와 after vowels, 과 after consonants.
• -하고: casual; works after vowels or consonants; common in speech.
• (이)랑: very casual; 랑 after vowels, 이랑 after consonants; often heard in daily conversation.
All three mean “and,” but formality and sound dictate which you choose.