oneureun doni eobseoseo sae sinbareul sal su eobseoyo.

-은/는 is the topic particle. In 오늘은, it marks today as the topic or frame for the sentence.

So 오늘은 feels like:

• As for today...
• Today, ...
• At least today, ...

It often gives a slight contrast too. In this sentence, 오늘은 can suggest something like:

• Today, I don’t have money, so I can’t buy new shoes
• maybe implying on another day it might be possible

You could say 오늘 돈이 없어서... without -은, but 오늘은 sounds more natural when setting up the situation for today.

Because 돈 is not the thing being bought. It is the thing that exists or does not exist.

The verb 없다 means to not exist / to not have. With 있다/없다, the thing that exists or does not exist usually takes -이/가.

So:

• 돈이 없다 = There is no money / I don’t have money

If you used 돈을, it would sound like money is the object of some action, which is not what is happening here.

In this sentence:

• 돈이 없어서 = because there is no money / because I don’t have money

없어서 comes from 없다 + -어서.

Breakdown:

• 없다 = to not exist, to not have
• -아서/어서 = because, so, and then

So 없어서 means:

• because there isn’t any
• because I don’t have it
• so there isn’t any

Here, it connects the reason to the result:

• 돈이 없어서 = because I don’t have money
• 새 신발을 살 수 없어요 = I can’t buy new shoes

Together:

• Because I don’t have money, I can’t buy new shoes

새 is a very common shortened modifier meaning new when it comes directly before a noun.

So both of these are possible:

• 새 신발
• 새로운 신발

They both mean new shoes.

The difference is mainly style and naturalness:

• 새 신발 is shorter and very common in everyday speech
• 새로운 신발 is a bit fuller or more descriptive

A useful thing to remember:

• 새 is used only directly before a noun
• you would not use it by itself as a standalone adjective in the same way as English new

So in this sentence, 새 신발 is perfectly natural.

살 수 없어요 means cannot buy or am not able to buy.

It is built like this:

• 사다 = to buy
• verb stem: 사-
• 살 = the form used before 수
• 수 = way, means, possibility
• 없어요 = there is not / do not have

So:

• 살 수 있어요 = can buy
• 살 수 없어요 = cannot buy

This is a very common Korean pattern:

• verb + -(으)ㄹ 수 있다 = can do
• verb + -(으)ㄹ 수 없다 = cannot do

Examples:

• 갈 수 있어요 = can go
• 갈 수 없어요 = cannot go
• 먹을 수 있어요 = can eat
• 먹을 수 없어요 = cannot eat

Because Korean changes the verb into a special form before 수 있다 / 수 없다.

The dictionary form is:

• 사다 = to buy

To use can/cannot, Korean uses:

• 사다 → 살 수 있다 / 살 수 없다

This happens because the pattern is:

• verb stem + -(으)ㄹ 수 있다/없다

For 사다:

• stem = 사-
• add -ㄹ 수
• 사 + ㄹ 수 → 살 수

So 살 수 없어요 is the correct form.

Because 신발 is the object of buy.

You are buying new shoes, so 신발 gets the object particle -을/를.

• 신발을 사다 = to buy shoes

Since 신발 ends in a consonant, it takes -을:

• consonant + -을
• vowel + -를

Examples:

• 책을 사다 = buy a book
• 신발을 사다 = buy shoes
• 우유를 사다 = buy milk

So in this sentence:

• 새 신발을 살 수 없어요 = I can’t buy new shoes

Yes. Korean word order is usually Subject/Topic + Object + Verb, and reasons often come before the main result.

This sentence is:

• 오늘은 = today / as for today
• 돈이 없어서 = because I don’t have money
• 새 신발을 = new shoes
• 살 수 없어요 = cannot buy

A very literal order would be:

• Today, because money is lacking, new shoes buy cannot

Natural English becomes:

• Today, because I don’t have money, I can’t buy new shoes

So the main differences are:

1. The reason comes before the result
2. The verb comes at the end
3. The object comes before the verb

In Korean, the subject is very often omitted when it is understood from context.

This sentence does not explicitly say I, but the natural meaning is:

• I don’t have money, so I can’t buy new shoes today

Korean often leaves out pronouns like I, you, he, or she if they are obvious.

So instead of saying:

• 저는 오늘은 돈이 없어서 새 신발을 살 수 없어요

people often simply say:

• 오늘은 돈이 없어서 새 신발을 살 수 없어요

This sounds natural and normal.

Yes, you could. Both can express a reason, but they are not always exactly the same in tone.

• 없어서 = because, so
• 없으니까 = because, since

In this sentence, both are possible:

• 돈이 없어서 새 신발을 살 수 없어요
• 돈이 없으니까 새 신발을 살 수 없어요

A simple way to think about the difference:

• -아서/어서 often sounds smoother and more neutral when linking cause and result
• -으니까 can sound a little more explicit or explanatory, sometimes like giving a reason to someone

For a straightforward statement like this, 없어서 is very natural.

없어요 is polite speech, often called the -아요/어요 style.

So the whole sentence is polite but not the most formal possible.

Levels you might compare:

• 없어 = casual
• 없어요 = polite
• 없습니다 = formal

Likewise:

• 살 수 없어 = casual
• 살 수 없어요 = polite
• 살 수 없습니다 = formal

So this sentence is appropriate for many everyday situations when speaking politely.

A natural pronunciation would sound roughly like this:

• 오늘은 → 오느른
• 돈이 → 도니
• 없어서 → 업서서
• 새 신발을 → 새 신바를
• 살 수 없어요 → 살 쑤 업서요

A few sound changes to notice:

• 돈이: the 이 attaches smoothly, so it sounds like 도니
• 없어서: ㅄ in 없 is pronounced like ㅂ before a consonant-like sound here, so it becomes 업서서
• 신발을: this often sounds like 신바를
• 수 after 살 can sound tense, closer to 쑤

You do not need to overthink every sound change at first, but recognizing them helps a lot with listening.