La vento havas grandan forton.

La is the definite article, meaning the. Esperanto has only one article, la, and it never changes.

So:

• la vento = the wind
• vento = wind or a wind, depending on context

In this sentence, la vento refers to the wind as a definite thing.

In Esperanto, nouns normally end in -o. So vento is a noun meaning wind.

This is one of the most basic patterns in Esperanto:

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

So vento is clearly a noun because of the -o ending.

Havas is the present-tense form of havi, meaning to have.

Esperanto verb endings are very regular:

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

So:

• havi = to have
• havas = has / have

Esperanto does not change the verb for different persons, so:

• mi havas = I have
• vi havas = you have
• la vento havas = the wind has

Granda is the basic adjective form, meaning big, great, or large. But here it becomes grandan because it describes a direct object.

In Esperanto, adjectives agree with the nouns they describe in:

• number: singular or plural
• case: especially whether the noun has the accusative -n

Since forton has -n, the adjective must match it:

• granda forto = a great force
• grandan forton = a great force, as a direct object

The -n ending marks the direct object in Esperanto. The direct object is the thing directly affected by the verb.

In this sentence:

• La vento = the subject
• havas = has
• grandan forton = what the wind has

So forto becomes forton because it is the direct object of havas.

Because adjectives must agree with the nouns they modify.

Here:

• forton is singular and accusative
• so grandan must also be singular and accusative

This agreement is very regular in Esperanto:

• granda forto = great force
• grandaj fortoj = great forces
• grandan forton = great force (direct object)
• grandajn fortojn = great forces (direct object)

No. That would be grammatically wrong.

After havas, the thing possessed is a direct object, so it needs -n:

• forto → forton

And the adjective must agree:

• granda → grandan

So the correct form is:

La vento havas grandan forton.

Forto can mean strength, force, or power, depending on context.

In this sentence, grandan forton means something like:

• great force
• great strength
• a lot of power

With wind, force is a very natural translation.

Yes, La vento estas forta is also natural, but it means something slightly different.

• La vento havas grandan forton = The wind has great force.
• La vento estas forta = The wind is strong.

These are close in meaning, but not identical in style. The first talks about the wind’s force as something it possesses; the second directly describes the wind as strong.

Yes, Esperanto word order is fairly flexible because the -n ending helps show what the direct object is.

The normal order is:

• La vento havas grandan forton.

But for emphasis, you could also say something like:

• Gravan forton havas la vento.
• Grandan forton la vento havas.

Those are less neutral and more marked in style. For learners, the standard subject-verb-object order is best.

A simple pronunciation guide is:

la VEN-to HA-vas gran-DAN FOR-ton

A few helpful points:

• Stress in Esperanto is always on the second-to-last syllable
• v is like English v
• t and d are clear, crisp sounds
• each vowel is pronounced clearly

Word by word:

• la
• vento = VEN-to
• havas = HA-vas
• grandan = gran-DAN
• forton = FOR-ton

Because adjective meaning depends on context. Granda often means big in a physical sense, but with abstract nouns like forto, it usually means great, strong, or considerable rather than physically large.

So:

• granda domo = a big house
• granda forto = great force / great strength

That is why grandan forton sounds natural as great force.