La festivalo komenciĝos morgaŭ.

La is the definite article, meaning the.

So la festivalo means the festival, not just a festival. Esperanto has only one article, la. There is no separate word for a/an.

In this sentence, la suggests that the festival is a specific one already known from the context.

In Esperanto, all singular nouns end in -o.

So:

• festivalo = festival
• festivaloj = festivals

Here it ends in -o because it is a singular noun.

Komenciĝos can be broken down like this:

• komenc- = begin / start
• -iĝ- = become, get into a state, happen to itself
• -os = future tense

So komenciĝos means will begin or will start.

The dictionary form is komenciĝi = to begin.

This is a very common question.

Komenci can mean to begin or to start, and it can sometimes be used with an object, as in start something.

Komenciĝi makes it especially clear that the subject itself is beginning. So:

• La festivalo komenciĝos = The festival will begin
• Li komencos la festivalon = He will start the festival

In real usage, komencos may also be heard for events in some contexts, but komenciĝos is very clear and natural here.

In Esperanto, tense is shown by the verb ending, not by a separate helper word like English will.

The main tense endings are:

• -as = present
• -is = past
• -os = future

So komenciĝos already includes the idea of will.

Morgaŭ means tomorrow.

Here it tells you when the festival will begin. It works like an adverb of time.

So the sentence structure is basically:

The festival + will begin + tomorrow

Yes. Esperanto word order is fairly flexible.

These are all possible:

• La festivalo komenciĝos morgaŭ.
• Morgaŭ la festivalo komenciĝos.

The original order is a neutral, natural one. Moving morgaŭ to the front can give it a little more emphasis.

There is no -n because there is no direct object here.

• La festivalo is the subject, so it does not take -n.
• Morgaŭ is a time word, not a direct object.

If there were a direct object, that noun would normally take -n.

Ĝ is pronounced like the j in judge.

So komenciĝos sounds roughly like:

ko-men-TSEE-jos

More exactly, the stress in Esperanto is always on the second-to-last syllable, so:

• fes-ti-VA-lo
• ko-men-ci-ĜOS
• mor-GAŬ

Yes, pretty much.

• La festivalo = The festival
• komenciĝos = will begin
• morgaŭ = tomorrow

So the word order is very close to English:

The festival will begin tomorrow.