geu chaegeun gilji anhaseo jumare ilgeul manhae.

Yes:

• 그 = that
• 책은 = book + topic marker 은
• 길지 않아서 = because it is not long
• 주말에 = on/over the weekend
• 읽을 만해 = it is worth reading / readable / manageable to read

So the structure is:

As for that book, because it isn’t long, it’s manageable enough to read over the weekend.

Literally, 그 책 means that book.

But in real conversation, 그 often points to something both speakers already know about. So depending on context, English might naturally translate it as either that book or the book.

So 그 책은 can feel like:

• that book, as for it...
• or the book we’re talking about...

은/는 marks the topic: as for that book...

Here, the speaker is making a comment about the book. That is why 책은 sounds natural.

If you used 책이, it would put more focus on the subject itself, as if answering Which book is manageable to read over the weekend? or highlighting the book more directly.

So:

• 그 책은... = As for that book...
• 그 책이... = That book (specifically) ...

Both can be possible in some contexts, but 은 is the more natural choice for a general comment.

Yes, 길다 basically means to be long, but Korean uses it for more than physical length.

With books, movies, speeches, and similar things, 길다 can describe length in terms of:

• amount of content
• duration
• how long it takes to get through

So for a book, 길다 means it’s long in the sense of a long book.

That is very natural Korean.

길지 않다 is the standard way to negate an adjective or verb.

It is built like this:

• 길다 = to be long
• 길지 않다 = to not be long

More generally:

• adjective/verb stem + -지 않다

Examples:

• 크다 → 크지 않다 = not big
• 재미있다 → 재미있지 않다 = not interesting
• 읽다 → 읽지 않다 = not read

So 길지 않아서 starts from 길지 않다.

Here, -아서/어서 gives a reason or cause, so it means because.

So:

• 길지 않아서 = because it isn’t long

This ending can also connect events in sequence, but in this sentence it clearly expresses reason.

So the logic is:

It’s not long, so / because of that, it’s manageable to read over the weekend.

읽을 만해 comes from 읽을 만하다.

This pattern means something like:

• worth reading
• readable
• good enough to read
• manageable enough to read

In this sentence, because the reason given is it isn’t long, the nuance is not only worth reading in the sense of quality. It also suggests it’s doable or not too demanding.

So here 주말에 읽을 만해 means something like:

• It’s manageable enough to read over the weekend
• It’s short enough that you could read it over the weekend
• It makes a good weekend read

Because -ㄹ/을 만하다 is a fixed grammar pattern.

It uses the attributive form 읽을 before 만하다:

• 읽다 → 읽을 만하다

You do not use 읽는 만하다 here.

This pattern does not literally mean future tense, even though -ㄹ/을 often has a future-like feeling. In this construction, it is just the correct form used before 만하다.

So the whole chunk 읽을 만하다 should be learned as one pattern.

No. This is a different 만.

In 읽을 만하다, 만 is part of the grammar pattern -ㄹ/을 만하다, which expresses that something is worth doing or sufficiently acceptable/doable.

So:

• 책만 읽어 = Read only the book
  → here 만 means only

But:

• 읽을 만하다 = worth reading / readable / doable to read
  → here 만 is part of a set expression, not only

That difference is important.

주말에 means on the weekend or over the weekend, depending on context.

The particle 에 is often used for time expressions to mark when something happens.

Examples:

• 월요일에 = on Monday
• 저녁에 = in the evening
• 주말에 = on/over the weekend

In this sentence, 주말에 읽을 만해 means the book is suitable to read during the weekend period.

Usually, that is the implication.

Because the speaker says the book is not long, and then says 주말에 읽을 만해, the natural idea is:

• it is realistic to read it over one weekend
• it is not too long or demanding for that time frame

It does not mathematically guarantee that every person will finish it, but that is the general feeling.

만해 is casual, non-polite speech.

The dictionary form is 만하다, and in this sentence it appears as the casual present form:

• 읽을 만하다 = dictionary form
• 읽을 만해 = casual spoken form
• 읽을 만해요 = polite spoken form
• 읽을 만합니다 = formal polite form

So the sentence can be changed to:

• 그 책은 길지 않아서 주말에 읽을 만해요.
  Polite everyday speech

It would sound less natural.

For descriptive adjectives like 길다, Korean usually prefers -지 않다 for neutral, standard negation:

• 길지 않아서 = natural
• 안 길어서 = understandable, but less standard/natural here

With many adjectives and verbs, 안 is possible, but -지 않다 is often smoother in careful or standard speech. In this sentence, 길지 않아서 is definitely the better choice.

Not always.

-ㄹ/을 만하다 can mean that something is:

• worth doing
• acceptable
• sufficiently good
• feasible or manageable

So it can express quality, practicality, or both.

In this sentence, because the reason is it isn’t long, the emphasis is strongly on practicality: the book is manageable for a weekend.

If you said something like 그 영화는 볼 만해, that often means the movie is worth watching in a more quality-based sense. But here the nuance is more doable than purely excellent.