Li klarigas la sencon de la portreto.

The -n marks the direct object in Esperanto.

In Li klarigas la sencon de la portreto:

• Li = the subject, the one doing the action
• klarigas = explains
• la sencon = what he explains

So senco becomes sencon because it is receiving the action of the verb.

This is very common in Esperanto:

• Mi vidas la hundon. = I see the dog.
• Ŝi legas la libron. = She reads the book.

Klarigi is the verb to explain / to make clear.

It is related to klara, which means clear.

A useful pattern in Esperanto is:

• -a = adjective: klara = clear
• -igi = to make something become that quality: klarigi = to make clear, explain

So:

• Li klaras would mean something like He is clear
• Li klarigas la sencon means He explains the meaning

And because la sencon is the direct object, it must take -n, so la senco would be wrong here.

De usually means of, and here it shows a relationship: the meaning of the portrait.

So the phrase breaks down like this:

• la senco = the meaning
• de la portreto = of the portrait

Together:

• la sencon de la portreto = the meaning of the portrait

This is one of the most basic uses of de in Esperanto: linking one noun to another.

Because both nouns are being treated as specific.

• la sencon = the specific meaning
• la portreto = the specific portrait

Esperanto uses la as its definite article, like English the.

So this sentence is not talking about just any meaning or any portrait, but a particular one already known from context.

Because portreto is not the direct object of the sentence.

The direct object is sencon, not portreto.

Compare the structure:

• Li klarigas [la sencon] [de la portreto].

Here:

• la sencon = the thing being explained
• de la portreto = a prepositional phrase describing that meaning

Nouns after a preposition like de do not normally take -n just because of the verb.

Yes, Esperanto word order is more flexible than English because the grammar endings show the roles.

For example, these would still be understandable:

• La sencon de la portreto li klarigas.
• Li la sencon de la portreto klarigas.

But Li klarigas la sencon de la portreto is the most neutral and natural order.

So although Esperanto allows flexibility, learners should usually start with:

• subject + verb + object

Usually yes in sentences like this, but it helps to understand the nuance.

Senco means:

• meaning
• sense
• significance

So la senco de la portreto can mean:

• what the portrait means
• the significance of the portrait
• the sense/message of the portrait

Depending on context, English might translate it in slightly different ways, but meaning is the most straightforward choice.

Yes. Li means he.

Esperanto personal pronouns include:

• mi = I
• vi = you
• li = he
• ŝi = she
• ĝi = it
• ni = we
• ili = they

So Li klarigas... specifically says that a male person is explaining something.

If the person were female, it would be:

• Ŝi klarigas la sencon de la portreto.

It is in the present tense.

Esperanto verb endings are very regular:

• -as = present
• -is = past
• -os = future
• -us = conditional
• -u = command / volitive
• -i = infinitive

So:

• klarigas = explains / is explaining
• klarigis = explained
• klarigos = will explain

Yes, that can also work, depending on style and word choice.

• klarigi = to make clear, explain
• ekspliki = to explain

In many contexts they are close in meaning. However, klarigi is especially common and has the nice literal sense of making something clear.

So Li klarigas la sencon de la portreto is perfectly natural Esperanto.

Yes. La sencon de la portreto is one noun phrase built around sencon.

The core noun is:

• sencon = meaning

And de la portreto adds information about that noun:

• of the portrait

So the sentence structure is:

• Li = subject
• klarigas = verb
• la sencon de la portreto = object phrase

A good way to test this is to ask:

• What does he explain?
• The meaning of the portrait.

That whole phrase is the answer.

A few things may be helpful for an English speaker:

• Li sounds like lee
• klarigas has stress on RI: kla-RI-gas
• sencon has stress on SEN: SEN-con
• portreto has stress on TRE: por-TRE-to

Esperanto stress is very regular: it falls on the second-to-last syllable.

Also:

• c is always like ts
• so sencon is pronounced roughly SEN-tson

That regular pronunciation is one of Esperanto’s easiest features once you get used to it.