Apenaŭ mi sendos avizon, la posedanto telefonos.

Here apenaŭ means something like hardly / scarcely ... when or more naturally in English as soon as.

So the idea is:

Apenaŭ mi sendos avizon, la posedanto telefonos.
= As soon as I send a notice, the owner will call.
= Hardly will I have sent a notice when the owner calls.

It emphasizes that the second action happens almost immediately after the first one.

Because both actions are in the future.

Esperanto often keeps the tense that matches the real time of each action. So if both things will happen later, both verbs can be future:

• mi sendos = I will send
• la posedanto telefonos = the owner will call

This is different from English, where we usually say As soon as I send..., not As soon as I will send.... English uses the present after words like when and as soon as, but Esperanto does not have to do that.

Yes. In this kind of sentence, apenaŭ can introduce the idea hardly ... when / as soon as without another word like kiam.

So this is a normal pattern:

• Apenaŭ X, Y.

A very close alternative would be:

• Tuj kiam mi sendos avizon, la posedanto telefonos.

That version may feel more straightforward to many learners, but the sentence with apenaŭ is fine and adds a sense of immediacy.

Because avizon is the direct object of sendos.

In Esperanto, the direct object takes -n:

• sendi avizon = to send a notice
• mi sendos avizon = I will send a notice

So the -n shows what is being sent.

Avizo means notice, notification, or sometimes announcement, depending on context.

So sendi avizon is to send a notice / notification.

If the meaning has already been given to you, the important grammar point is that it is just a normal noun here, and it takes -n because it is the object.

Posedanto means owner or possessor.

It comes from:

• posedi = to possess, to own
• -ant- = active present participle, meaning someone who is doing the action
• -o = noun ending

So posedanto literally means one who possesses.

Depending on context, it could mean:

• owner
• proprietor
• landlord

La means the.

So la posedanto means the owner—a specific owner that the speaker and listener can identify from context.

This is the same basic idea as in English. The sentence is not talking about just any owner, but about the relevant one.

After.

The meaning is that first you send the notice, and then almost immediately afterward the owner calls.

So the order is:

1. mi sendos avizon
2. la posedanto telefonos

The word apenaŭ suggests there is barely any delay between the two actions.

Yes, the comma is normal and helpful here because it separates the two clauses:

• Apenaŭ mi sendos avizon, la posedanto telefonos.

Esperanto often uses commas between clauses more regularly than English does. In this sentence, the comma clearly marks the break between the time clause and the main clause.

Yes, but this order is natural because it presents the first action before the second one.

The given sentence focuses on the trigger event first:

• Apenaŭ mi sendos avizon, la posedanto telefonos.

A clearer alternative for many learners would be:

• Tuj kiam mi sendos avizon, la posedanto telefonos.

So the original word order is fine; it just has a slightly more literary or emphatic feel because of apenaŭ.

It is understandable and correct, but many learners will find tuj kiam easier and more transparent in everyday use.

Compare:

• Apenaŭ mi sendos avizon, la posedanto telefonos.
• Tuj kiam mi sendos avizon, la posedanto telefonos.

Both express that the call will come right after the notice is sent. The version with apenaŭ has a stronger feeling of barely any time passes before the next thing happens.