Tiu verko estas longa sed bela.

Tiu means that or that one.

In Tiu verko, it works like a demonstrative determiner: that work.

A useful comparison:

• tiu verko = that work
• ĉi tiu verko = this work

So tiu usually points to something a bit more distant, while ĉi tiu points to something nearer.

Verko means a work, usually in the sense of a created work, especially an artistic, literary, or intellectual one.

Depending on context, it could mean things like:

• a literary work
• a piece of art
• a composition
• a work in a general creative sense

So in this sentence, verko is not just any kind of job or labor. It is more like a work / creation.

Estas is the present tense of esti, which means to be.

So:

• esti = to be
• estas = is / am / are

Esperanto uses the same present-tense form for all persons:

• mi estas = I am
• vi estas = you are
• li estas = he is
• ĝi estas = it is

That makes things simpler than English.

In Esperanto, adjectives always end in -a.

So:

• longa = long
• bela = beautiful

That -a ending shows that the word is an adjective, no matter where it appears in the sentence.

A few more examples:

• granda = big
• interesa = interesting
• nova = new

They match the noun they describe.

Here, verko is singular, so the adjectives are also singular:

• verko = work
• longa, bela = singular adjective forms

If the noun were plural, the adjectives would also become plural:

• Tiuj verkoj estas longaj sed belaj.
• Those works are long but beautiful.

So Esperanto adjectives agree with the noun in number, and also in case when needed.

The -n ending usually marks the direct object, and there is no direct object here.

This sentence is just:

• subject: Tiu verko
• verb: estas
• predicate adjectives: longa, bela

Since verko is the subject, not an object, it does not take -n.

And the adjectives after estas also do not take -n here, because they are describing the subject, not acting as direct objects.

Because tiu already makes the noun definite.

In Esperanto, la means the, but you usually do not use la together with tiu in a phrase like this.

So:

• la verko = the work
• tiu verko = that work

Using both would normally be unnecessary.

Sed means but.

It connects two contrasting ideas:

• longa = long
• bela = beautiful
• longa sed bela = long but beautiful

It works very much like English but.

More examples:

• Li estas juna sed saĝa. = He is young but wise.
• La libro estas malmultekosta sed bona. = The book is cheap but good.

The normal order here is very natural:

• Tiu verko = subject
• estas = verb
• longa sed bela = description

So Tiu verko estas longa sed bela is the standard way to say it.

Esperanto word order is somewhat flexible, but not all rearrangements sound equally natural. For learners, the safest pattern is:

subject + verb + complement

So this sentence is a good model to follow.

Yes. Tiu verko estas bela sed longa is grammatically correct too.

The difference is mainly emphasis:

• longa sed bela suggests: it is long, but despite that, it is beautiful
• bela sed longa suggests: it is beautiful, but it is also long

So both are possible, but the original order highlights the contrast in a particular way.

It would become:

Tiuj verkoj estas longaj sed belaj.

Changes:

• tiu → tiuj = that/those
• verko → verkoj = work/works
• longa → longaj
• bela → belaj

This shows an important Esperanto rule: adjectives agree with the noun in number.

A rough pronunciation guide is:

TEE-oo VEHR-ko EH-stas LON-ga sed BEH-la

A few helpful points:

• tiu is two vowel sounds together: ti-u
• stress in Esperanto is usually on the second-to-last syllable
• so the stressed syllables are:
  • TI-u
  • VER-ko
  • ES-tas
  • LON-ga
  • BE-la

Esperanto pronunciation is very regular, so once you learn the sound of each letter, sentences like this become easy to read aloud.