La pordo estas fermita.

In Esperanto, all nouns end in -o. So pordo is a noun meaning door.

This is one of the most basic and helpful patterns in the language:

• -o = noun
• -a = adjective
• -e = adverb
• -i = infinitive verb

So seeing pord-o immediately tells you it is a noun.

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

So:

• mi estas = I am
• vi estas = you are
• li/ŝi estas = he/she is
• la pordo estas = the door is

Esperanto verbs do not change according to the subject. Estas stays estas no matter who or what the subject is.

Because this sentence is not saying that the door is doing the action of closing. It is describing the door's state: it is in a closed condition.

• fermas = closes / is closing (an active verb form)
• fermita = closed (a passive participle used like an adjective)

So La pordo estas fermita means the door is closed, not the door closes.

Yes, in this sentence it behaves like an adjective.

Fermita is a participle, more specifically the past passive participle of fermi (to close). But in practice here it works adjectivally and describes pordo.

You can think of it as:

• fermi = to close
• fermita = closed

So La pordo estas fermita is literally something like The door is closed.

Because adjectives in Esperanto end in -a.

Since fermita is describing the noun pordo, it takes the adjective ending:

• pordo = door
• fermita pordo = a closed door

In La pordo estas fermita, the adjective comes after estas, but it still describes pordo.

Because it is singular and not accusative here.

Esperanto adjectives agree with the nouns they describe:

• singular: no -j
• plural: add -j
• accusative: add -n

Examples:

• La pordo estas fermita. = The door is closed.
• La pordoj estas fermitaj. = The doors are closed.

There is no -n here because la pordo is the subject of the sentence, not the direct object.

Because pordo is the subject, not the object.

The accusative ending -n is usually used for the direct object. In this sentence, the door is the thing being talked about, so it is the subject:

• La pordo estas fermita. = The door is closed.

If door were a direct object, then you would use -n, for example:

• Mi fermas la pordon. = I close the door.

So:

• pordo = subject
• pordon = direct object

Its main meaning here is the state: the door is in a closed condition.

Because fermita is a passive participle, it can also carry the idea that the door has been closed, but in everyday use this sentence is usually understood simply as The door is closed.

So the focus is on the result, not on who did it.

Yes, but it means something slightly different.

• La pordo estas fermita. = The door is closed.
  This describes the door's current state.

• La pordo fermiĝis. = The door closed / became closed.
  This describes the change or event.

So:

• estas fermita = state
• fermiĝis = action/change into that state

That is a very common and useful distinction in Esperanto.

The root is ferm-, which relates to closing.

From that root you can build several words:

• fermi = to close
• fermas = closes / is closing
• fermita = closed
• fermo = closing, closure
• malfermi = to open

This is one of the strengths of Esperanto: once you know the root and the endings, many words become easy to recognize.

Yes, Esperanto word order is fairly flexible, but La pordo estas fermita is the most natural neutral order.

You may sometimes see variations for emphasis, but beginners should usually stick to:

• subject + estas
  • adjective/participle

So this sentence is a very standard model:

• La pordo estas fermita.

It is pronounced roughly fer-MEE-ta.

A simple breakdown:

• fer as in fair but shorter
• mi like mee
• ta like tah

And remember that Esperanto stress is always on the second-to-last syllable, so in fer-mi-ta, the stress is on mi.