La hieraŭ aĉetita libro estas sur la tablo.

Aĉetita is the past passive participle of aĉeti (to buy).

It breaks down like this:

• aĉet- = the root meaning buy
• -it- = past passive participle, meaning having been ...ed
• -a = adjective ending

So aĉetita means bought or more literally having been bought.

In this sentence, la hieraŭ aĉetita libro means the book bought yesterday.

It ends in -a because it is functioning as an adjective and describes libro.

In Esperanto, adjectives always end in -a.

So here:

• libro = book
• aĉetita = bought

Since aĉetita describes what kind of book it is, it takes the adjective ending:

• la hieraŭ aĉetita libro = the yesterday-bought book = the book bought yesterday

Hieraŭ means yesterday, and here it modifies the participle aĉetita.

So the idea is:

• hieraŭ aĉetita = bought yesterday

This word order is natural in Esperanto. The adverb comes before the participle it modifies.

You can think of it as a shortened relative clause:

• la libro, kiu estis aĉetita hieraŭ = the book which was bought yesterday

But Esperanto often prefers the more compact participial form:

• la hieraŭ aĉetita libro

Yes. That is the most natural way to understand it.

Esperanto often uses participles where English uses:

• a reduced relative clause: the book bought yesterday
• or a full clause: the book that was bought yesterday

So:

• la hieraŭ aĉetita libro
• = the book bought yesterday
• = the book that was bought yesterday

All of these express the same basic idea.

Because both nouns are definite.

• la libro = the book
• la tablo = the table

Esperanto uses la much like English uses the. If both the book and the table are understood to be specific, both can take la.

So:

• La hieraŭ aĉetita libro = The book bought yesterday
• estas sur la tablo = is on the table

There is no -n because neither word is a direct object here.

The sentence structure is:

• La hieraŭ aĉetita libro = the subject
• estas = is
• sur la tablo = a prepositional phrase meaning on the table

Important points:

• The subject does not take -n
• A noun after a preposition like sur usually does not take -n

So:

• libro has no -n because it is the subject
• tablo has no -n because it follows sur

If you saw sur la tablon, that would usually suggest motion onto the table, not simple location.

It literally means is on the table.

Breakdown:

• estas = is
• sur = on
• la tablo = the table

So the whole sentence is built very straightforwardly:

• La hieraŭ aĉetita libro = The book bought yesterday
• estas sur la tablo = is on the table

Yes, that is also understandable and natural.

Both of these work:

• La hieraŭ aĉetita libro estas sur la tablo
• La libro aĉetita hieraŭ estas sur la tablo

The first version keeps hieraŭ aĉetita together before the noun. The second puts libro first and then adds the participial description after it.

The first version may feel a bit more compact and tightly grouped as the yesterday-bought book. The second may feel closer to the book bought yesterday in English word order.

Yes. A fuller version would be:

• La libro, kiu estis aĉetita hieraŭ, estas sur la tablo.

That means:

• The book, which was bought yesterday, is on the table.

This is grammatically fine, but it is longer. Esperanto often prefers the shorter participial form when the meaning is clear:

• La hieraŭ aĉetita libro estas sur la tablo.

The pattern is:

• [noun phrase with adjective/participle] + estas + [prepositional phrase]

More specifically:

• La hieraŭ aĉetita libro = subject noun phrase
• estas = linking verb
• sur la tablo = location

So the sentence means:

• a specific book
• identified as the one bought yesterday
• is located on the table

This is a very common Esperanto structure.