eonnineun saengseonboda sogogireul deo johahajiman, jeoneun dwaejigogirang sangchureul gati meogeul ttaega jeil masisseoyo.

는 is the topic marker. Here, 언니는 sets up older sister as the topic and gives a contrastive feeling, something like:

• As for my older sister, she likes beef more than fish...

Using 가 would sound more like you are simply identifying who likes beef more than fish. With 는, the sentence feels more natural in a comparison, especially because the speaker then contrasts that with 저는 in the second half.

So the pair 언니는 ... 저는 ... creates a clear contrast:

• My older sister likes beef more than fish, but I think pork and lettuce are best together.

언니 means older sister, but only when said by a female speaker.

It can refer to:

• your actual older sister
• a close older female friend
• sometimes a slightly older woman you are close to

A male speaker would normally say 누나 instead.

So if the sentence says 언니는, it strongly suggests the speaker is female.

This is the standard Korean comparative pattern:

• A보다 B를 더 좋아하다 = to like B more than A

In this sentence:

• 생선보다 = than fish
• 소고기를 = beef
• 더 좋아하지만 = like more, but...

So:

• 언니는 생선보다 소고기를 더 좋아하지만
• My older sister likes beef more than fish, but...

A key point for English speakers: Korean often uses:

• 보다 = than
• 더 = more

So the pattern is very direct.

Not always, but using both is very common and natural.

For example:

• 생선보다 소고기를 더 좋아해요.
• I like beef more than fish.

Sometimes 더 can be omitted if the meaning is already clear:

• 생선보다 소고기를 좋아해요.

This still means I like beef more than fish, but 더 makes the comparison more explicit and natural.

So in this sentence, 보다 + 더 is a very normal combination.

좋아하지만 combines:

• 좋아하- = like
• -지만 = but / although

So:

• 좋아하지만 = like, but...

This is a very common way to connect two clauses in Korean.

Compare:

• 좋아해요. 하지만 ... = I like it. But ...
• 좋아하지만 ... = I like it, but ...

The second version is smoother and more natural inside one sentence.

저는 means as for me / I, with the topic marker 는.

It is used here for contrast:

• 언니는 ...
• 저는 ...

That contrast is important. It shows:

• My older sister prefers beef to fish,
• but I think pork and lettuce together are the most delicious.

If the speaker said 제가, it would put more focus on I as the subject. But 저는 sounds more like as for me, in contrast..., which fits this sentence very well.

This is a very common Korean pattern.

• 돼지고기랑 상추를 = pork and lettuce (as the object)

Here, 랑 means and or with in casual speech.

So the structure is:

• 돼지고기랑 상추를 같이 먹다
• to eat pork and lettuce together

Even though both nouns are part of the object, Korean often puts the object particle only on the second noun in this kind of list:

• A랑 B를 먹다
• eat A and B

So 를 applies to the whole phrase, not just to 상추 alone.

They can all mean and / with, but the tone is different.

• 랑 / 이랑: casual, conversational
• 하고: also common and conversational
• 와 / 과: more formal or written

So:

• 돼지고기랑 상추를 sounds natural in everyday speech.

You could also say:

• 돼지고기하고 상추를
• 돼지고기와 상추를

But 랑 fits the casual, spoken style of this sentence best.

같이 먹을 때 means when (I) eat them together.

Breakdown:

• 같이 = together
• 먹을 = will eat / eat (modifier form of 먹다)
• 때 = time, when

So 먹을 때 literally means the time when [someone] eats.

In natural English, this is usually translated as:

• when I eat pork and lettuce together

A very important point: Korean often leaves the subject unstated when it is obvious from context. Here, it is understood as I because the speaker has already said 저는.

This is one of the trickier parts for English speakers.

Literally, 먹을 때가 제일 맛있어요 is something like:

• The time when I eat them together is the most delicious

That sounds odd in English, but in Korean it naturally means:

• They taste best when I eat them together
• It is most delicious when I eat pork and lettuce together

The 가 marks 먹을 때 as the thing being focused on:

• that time / that situation is when it tastes best

So 때가 제일 맛있어요 does not mean the time itself is delicious in a literal way. It means that situation is the most delicious / enjoyable in terms of taste.

Because 제일 means the most, while 더 means more.

• 더 맛있어요 = more delicious / tastier
• 제일 맛있어요 = the most delicious / tastes best

In this sentence, the speaker is not just comparing two things once. They are saying that, for them, the best-tasting situation is eating pork and lettuce together.

So:

• 돼지고기랑 상추를 같이 먹을 때가 제일 맛있어요
• Pork and lettuce taste best when eaten together

Because they express different ideas.

• 좋아하다 = to like / prefer
• 맛있다 = to be delicious / to taste good

First half:

• 언니는 생선보다 소고기를 더 좋아하지만
• The older sister’s preference is being described.

Second half:

• 저는 돼지고기랑 상추를 같이 먹을 때가 제일 맛있어요
• The speaker is talking about taste, not just preference.

So the sentence contrasts:

• what the sister prefers with
• what tastes best to the speaker

It describes the eating combination/situation as tasty.

Korean often allows this kind of expression where English would reorganize the sentence. The idea is:

• When I eat pork and lettuce together, it tastes the best.

So even though the grammar centers on 먹을 때가, the meaning is really about the food combination being best in that situation.

A more explicitly food-centered version might be:

• 돼지고기랑 상추를 같이 먹으면 제일 맛있어요.
• Pork and lettuce taste best when eaten together.

Your original sentence is still perfectly natural.

Yes. A very natural alternative would be:

• 돼지고기랑 상추를 같이 먹으면 제일 맛있어요.

This means:

• If/when I eat pork and lettuce together, it tastes best.

The difference is small:

• 먹을 때 focuses on the time/occasion when eating
• 먹으면 focuses on the condition of eating them together

Both are natural, but 먹을 때가 제일 맛있어요 has a slightly more descriptive, situational feel.

It is polite but conversational.

Signs of that include:

• 좋아하지만
• 저는
• 맛있어요
• 랑

The ending -어요 makes it polite, but 랑 keeps it sounding natural and spoken rather than formal or stiff.

So this sentence sounds like something someone might actually say in everyday conversation.