La lampo estas ŝaltita.

• la = the
• lampo = lamp
• estas = is / are / am (present tense of esti, to be)
• ŝaltita = switched on / turned on

So grammatically, the sentence is:

the lamp + is + switched on

La is Esperanto’s definite article, meaning the.

So la lampo means the lamp, not just a lamp.

A useful point: Esperanto has no indefinite article. So:

• lampo = a lamp or just lamp
• la lampo = the lamp

In Esperanto, all nouns end in -o.

So:

• lamp- = the root
• lampo = lamp

This is one of the most regular features of Esperanto. If you see -o, you can usually identify the word as a noun right away.

Ŝaltita is a participle used like an adjective.

It comes from the verb ŝalti, meaning to switch on / turn on.

Because it describes lampo, it takes the adjective ending -a:

• ŝaltita = switched on

So it behaves like an adjective in the sentence, even though it comes from a verb.

Because it is describing the noun lampo, not naming a thing by itself.

In Esperanto:

• nouns end in -o
• adjectives end in -a

So:

• lampo = a noun
• ŝaltita = an adjective-like participle describing the lamp

If the noun were plural, the adjective would agree:

• La lampoj estas ŝaltitaj = The lamps are switched on

Because ŝalti normally means to switch on something. It is a verb of action done to an object.

So:

• Mi ŝaltas la lampon = I switch on the lamp

But in your sentence, the lamp is not doing the action. It is in the state resulting from that action. That is why Esperanto uses:

esti + participle

• estas ŝaltita = is switched on / is on

A related form is:

• La lampo ŝaltiĝas = The lamp is turning on / gets switched on

So:

• ŝaltiĝas = the change into the on-state
• estas ŝaltita = the state of already being on

Not exactly in the same way as an English past tense.

The -it- part shows that the action of switching on is completed. But the tense of the whole sentence comes from estas, which is present tense.

So La lampo estas ŝaltita means:

• the lamp is now in the state of having been switched on
• in natural English: The lamp is on or The lamp is switched on

So the sentence is present in time, even though the participle suggests a completed action behind the state.

Because there is no direct object in this sentence.

• La lampo is the subject
• ŝaltita is part of the predicate after estas

The accusative -n is usually used for direct objects, such as in:

• Mi ŝaltas la lampon = I switch on the lamp

Here, though, the lamp is not an object. It is the thing being described:

• La lampo estas ŝaltita

So no -n is needed.

Yes, Esperanto word order is fairly flexible, because endings show the grammatical roles clearly.

The neutral, most natural order is:

• La lampo estas ŝaltita

But other orders are possible for emphasis or style, for example:

• Ŝaltita estas la lampo

That sounds more marked or literary. For ordinary use, the original order is best.

A simple guide:

• ŝ sounds like English sh
• stress in Esperanto is always on the second-to-last syllable

So ŝaltita is pronounced approximately:

shal-TEE-ta

And the full sentence is roughly:

LAH LAM-po ES-tas shal-TEE-ta

These are different passive participles from ŝalti:

• ŝaltata = being switched on
• ŝaltita = switched on / having been switched on
• ŝaltota = about to be switched on

So:

• La lampo estas ŝaltata = The lamp is being switched on
• La lampo estas ŝaltita = The lamp is switched on / is on
• La lampo estas ŝaltota = The lamp is about to be switched on

In your sentence, ŝaltita is used because the lamp is already in the on-state.