Se la baterio de mia telefono ne estas ŝargita, mi ne respondas al via mesaĝo.

Se means if. It introduces a condition.

So the sentence has two parts:

• Se la baterio de mia telefono ne estas ŝargita = If the battery of my phone is not charged
• mi ne respondas al via mesaĝo = I do not reply to your message

This is the normal way to build an if sentence in Esperanto.

Because this sentence expresses a general situation or habitual truth, not one specific future event.

So it means something like:

• Whenever my phone battery isn’t charged, I don’t reply to your message.

In Esperanto, present tense is often used this way.

If you wanted a specific future meaning, you could say:

• Se la baterio de mia telefono ne estos ŝargita, mi ne respondos al via mesaĝo.
  = If my phone battery is not charged, I will not reply to your message.

This is a possession structure.

• la baterio = the battery
• de mia telefono = of my phone

So literally it is the battery of my phone.

Esperanto often uses de to show possession or relationship, especially when English uses of or 's.

You could think of it as:

• la baterio de mia telefono = my phone’s battery

In Esperanto, possessive words like mia, via, lia, ŝia, etc. usually make the noun definite by themselves.

So you normally say:

• mia telefono = my phone
• not la mia telefono

But in la baterio de mia telefono, the noun baterio is a separate noun phrase, so it can still take la:

• la baterio = the battery
• de mia telefono = of my phone

That is completely normal.

Yes, you might hear something like that, but it is not exactly the same.

• la baterio de mia telefono clearly means the battery of my phone
• mia telefona baterio means more literally my phone-related battery or my telephone battery

The de phrase is clearer and more natural when you mean the battery belonging to a specific phone.

Because ŝargita is a participle meaning charged.

• ŝargi = to charge
• ŝargita = charged

So:

• estas ŝargita = is charged
• ne estas ŝargita = is not charged

This is very similar to English. The battery is not doing the action; it is in the state of having been charged.

Ŝargita is a past passive participle used like an adjective.

That is why it ends in -a.

In Esperanto:

• adjective ending = -a
• noun ending = -o
• adverb ending = -e

So ŝargita behaves like an adjective describing baterio.

It agrees with the noun in number and accusative marking if needed. Here it is:

• singular
• not accusative

So ŝargita stays in the basic form -a.

Because respondi normally goes with al when you mean reply to someone or something.

So:

• respondi al iu = reply to someone
• respondi al io = reply to something

That gives us:

• mi respondas al via mesaĝo = I reply to your message

English sometimes uses answer directly, but Esperanto often uses the pattern respondi al.

Because it is after the preposition al.

In Esperanto, a noun after a preposition usually does not take -n for direct object.

So here:

• al via mesaĝo = to your message

The -n ending marks a direct object, but via mesaĝo is not a direct object here. It is part of the prepositional phrase al via mesaĝo.

Yes. Esperanto word order is fairly flexible.

You could also say:

• Mi ne respondas al via mesaĝo, se la baterio de mia telefono ne estas ŝargita.

That means the same thing.

Putting the Se... clause first is very common because it sets up the condition before the main statement.

Because the sentence begins with a subordinate if-clause, and the comma separates it from the main clause.

So the structure is:

• Se ..., mi ne respondas ...

This comma is standard and helps readability.

It can mean either one.

Esperanto via does not distinguish:

• singular your
• plural your

So via mesaĝo could mean your message when speaking to one person or, depending on context, to more than one person.

Usually the context makes it clear.