La lavita tuko estas sur la seĝo.

Lavita means washed.

It comes from:

• lavi = to wash
• -it- = a passive participle showing a completed action
• -a = adjective ending

So:

• lavita tuko = a washed towel/cloth
• literally, a towel that has been washed

This is very common in Esperanto: participles can work like adjectives.

Because it is an adjective describing tuko.

In Esperanto, adjectives always end in -a:

• bona = good
• granda = big
• lavita = washed

Here lavita describes what kind of towel/cloth it is, so it must have the adjective ending -a.

La is the definite article, meaning the.

So:

• la lavita tuko = the washed towel
• lavita tuko = washed towel / a washed towel, depending on context

Esperanto has only one article, la, and it does not change for gender, number, or case.

Because there are two separate noun phrases, and each can be definite on its own:

• la lavita tuko = the washed towel
• la seĝo = the chair

English does the same:

• The washed towel is on the chair.

Each noun can take the if it is specific.

Esperanto normally has no indefinite article.

So:

• tuko can mean a towel, a cloth, or just towel/cloth depending on context
• seĝo can mean a chair

If Esperanto wants to say the, it uses la.
If there is no la, the meaning is usually indefinite or general.

So Esperanto distinguishes:

• tuko = a towel / towel
• la tuko = the towel

They are different kinds of words:

• lavita = washed; an adjective/participle
• lavis = washed; a past-tense verb

Examples:

• La tuko estas lavita. = The towel is washed / has been washed.
• Ŝi lavis la tukon. = She washed the towel.

So in your sentence, lavita describes the towel. It is not the main verb.

The main verb is estas.

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

So the sentence structure is:

• La lavita tuko = the subject
• estas = the verb
• sur la seĝo = a prepositional phrase meaning where it is

So literally:

• The washed towel is on the chair.

Because neither word is a direct object here.

• tuko is the subject
• seĝo is part of the phrase sur la seĝo, which shows location

In Esperanto, the accusative -n is usually used for:

1. a direct object
2. movement toward something in some expressions

Here there is no direct object, so no -n.

Because the sentence describes location, not movement.

• sur la seĝo = on the chair (it is already there)
• sur la seĝon = onto the chair (movement toward the chair)

Compare:

• La tuko estas sur la seĝo. = The towel is on the chair.
• Mi metas la tukon sur la seĝon. = I put the towel onto the chair.

This is an important Esperanto pattern.

Yes, but before the noun is more normal in many cases.

• la lavita tuko = the usual order
• la tuko lavita = possible, but often feels more marked, poetic, or emphatic

Beginners should usually place adjectives before the noun unless they have a reason not to.

Yes. Adjectives in Esperanto agree with the noun in number and case.

Here:

• tuko = singular, no accusative
• so lavita is also singular, no accusative

If the noun changed, the adjective would change too:

• la lavitaj tukoj = the washed towels
• mi vidas la lavitan tukon = I see the washed towel

So adjective agreement is very regular in Esperanto.

Tuko is a general word for a piece of cloth or cloth item, and depending on context it can be translated as:

• cloth
• towel
• rag
• sometimes another fabric item

So the exact English translation depends on context. If the meaning shown to the learner is towel, that is fine, but the Esperanto word itself is somewhat broader than one exact English word.

Roughly:

• se like se in set
• ĝ sounds like the j in judge
• o is a pure o sound, like in many European languages

So seĝo is approximately SEH-jo.

Also useful:

• ĝ = English j sound
• ŝ = English sh
• ĉ = English ch
• ĵ = the sound of s in measure
• ŭ = a short w-like glide

Yes. Esperanto word order is fairly flexible because endings show the grammar.

For example, you could also say:

• Sur la seĝo estas la lavita tuko.

This still means essentially the same thing, but it gives more focus to the location first: On the chair is the washed towel.

Still, for learners, subject + verb + rest is usually the safest and clearest order:

• La lavita tuko estas sur la seĝo.

The active idea would be something like:

• Iu lavis la tukon. = Someone washed the towel.

Then the result can be described with the participle:

• La tuko estas lavita. = The towel is washed / has been washed.

So lavita focuses on the towel as something that received the action of washing.

You would make both the noun and the adjective plural:

• La lavitaj tukoj estas sur la seĝo.

Breakdown:

• tuko → tukoj = towels
• lavita → lavitaj = washed

This shows Esperanto adjective agreement very clearly.