La bruo de la vento vekas la infanon.

Because Esperanto uses la separately for each noun that is definite.

• la bruo = the noise
• la vento = the wind

So La bruo de la vento literally means the noise of the wind.

English sometimes uses the less consistently in similar phrases, but in Esperanto, if both nouns are definite, each one normally gets its own la.

de usually means of, from, or sometimes shows possession or source.

In this sentence:

• la bruo de la vento = the noise of the wind

So de la vento tells you what the noise comes from or belongs to. It is very similar to English of the wind.

Because bruo is the subject of the sentence, not the direct object.

Esperanto uses -n on the direct object:

• La bruo = the noise → subject
• la infanon = the child → direct object

The sentence structure is:

• La bruo de la vento = the thing doing the action
• vekas = wakes
• la infanon = the one being woken

So only infanon gets -n.

Because la infanon is the direct object of vekas.

In Esperanto, the direct object usually takes the ending -n.

• infano = child
• infanon = child as a direct object

Compare:

• La infano vekas la patron. = The child wakes the father.
• La patro vekas la infanon. = The father wakes the child.

The -n helps show who is doing the action and who receives it.

vekas is the present-tense form of the verb veki, meaning to wake or to awaken.

Esperanto verb endings are very regular:

• veki = to wake
• vekas = wakes / is waking
• vekis = woke
• vekos = will wake
• vekus = would wake
• veku = wake! / let ... wake

So vekas tells you the action is in the present.

It can mean either, depending on context.

Esperanto present tense -as does not force the same distinction English does between:

• wakes
• is waking

So La bruo de la vento vekas la infanon could mean:

• The noise of the wind wakes the child
• The noise of the wind is waking the child

Usually the broader context makes the intended meaning clear.

Yes, to some extent.

Because Esperanto marks the direct object with -n, word order is more flexible than in English. The basic order here is very natural:

• La bruo de la vento vekas la infanon.

But other orders are possible, for example:

• La infanon vekas la bruo de la vento.

This still means the same thing, because la infanon has -n, so it is still the object.

That said, the original order is the most straightforward and neutral.

Sometimes Esperanto does use compound words, and something like ventbruo could be understandable as wind-noise.

However, la bruo de la vento is very clear and completely normal. For a learner, it is often easier to understand because it matches the idea the noise of the wind very directly.

So:

• la bruo de la vento = very transparent, ordinary
• la ventbruo = possible compound, but less basic

Because the sentence is talking about the wind as a general single phenomenon, not the winds.

• vento = wind
• ventoj = winds

English also usually says the wind in this kind of sentence, so Esperanto does the same here.

infano usually means child.

It refers to a young person in general, not specifically a baby. If you wanted infant in the sense of a very young baby, another word might be more precise depending on context.

So for most learners, the safest understanding is:

• infano = child

Esperanto normally uses de instead of an apostrophe-style possessive.

So where English can say:

• the wind’s noise
• the noise of the wind

Esperanto uses:

• la bruo de la vento

This is the standard and natural way to express that relationship.

Yes, veki is the basic verb meaning to wake or to awaken someone or something.

A related intransitive form is:

• veki = to wake someone
• vekiĝi = to wake up, become awake

So in this sentence:

• vekas la infanon = wakes the child

If the child were waking up on their own, Esperanto would more likely use vekiĝas.

The full subject is La bruo de la vento.

The head noun is bruo. The phrase de la vento just modifies it and tells what kind of noise it is.

So the structure is:

• La bruo = the noise
• de la vento = of the wind

Together:

• La bruo de la vento = the noise of the wind

That whole phrase is the subject that performs the action vekas.