Ni ricevis avizon pri la hejtado.

Because avizon is the direct object of ricevis.

In Esperanto, the direct object takes the -n ending:

• Ni ricevis avizon. = We received a notice.
• Mi vidas la domon. = I see the house.

The subject ni does not take -n, because it is the one doing the action.

Ricevis comes from the verb ricevi, meaning to receive.

The ending -is shows the past tense in Esperanto:

• ricevas = receive / am receiving
• ricevis = received
• ricevos = will receive

So Ni ricevis means We received.

La is the definite article, meaning the.

So:

• hejtado = heating, heating process, heating in general
• la hejtado = the heating, the specific heating being talked about

In this sentence, it probably refers to a particular heating system or a specific heating matter already known from context, so la is natural.

Pri means about, concerning, or regarding.

So:

• avizo pri la hejtado = a notice about the heating

It introduces the topic of the notice.

Some other examples:

• libro pri historio = a book about history
• demando pri la kurso = a question about the course

Hejti means to heat.
Hejtado is the noun form meaning heating.

The ending -ado often shows an ongoing process, repeated action, or activity:

• hejti = to heat
• hejtado = heating

Depending on context, la hejtado can mean:

• the heating process
• the heating system
• the heating service in a building

A learner should notice that Esperanto often builds related words very regularly from the same root.

This is the most straightforward Esperanto word order:

• Ni = subject
• ricevis = verb
• avizon = direct object
• pri la hejtado = prepositional phrase modifying avizon

So it works like: We received [a notice] [about the heating].

Because Esperanto marks the direct object with -n, word order is more flexible than in English, but this normal order is the easiest and most common.

Most naturally, it connects to avizon.

So the sentence means:

• We received a notice about the heating.

Not:

• We received a notice, and the receiving was somehow about the heating.

Grammatically, pri la hejtado could be understood through the whole idea, but in practice it most clearly describes what kind of notice it was.

No, not in standard Esperanto.

It must be avizon, because it is the direct object. Without -n, the grammar is wrong.

Esperanto relies heavily on endings:

• ni = subject pronoun
• ricevis = past-tense verb
• avizon = direct object

That -n is one of the most important endings to watch for.

Avizo is a noun. The ending -o marks nouns in Esperanto.

Here are the forms:

• avizo = notice
• avizon = notice (direct object form)
• avizoj = notices
• avizojn = notices (direct object plural)

This is part of Esperanto’s very regular ending system:

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

Normally, Esperanto uses the subject pronoun unless the subject is already very clear from context.

So the full sentence:

• Ni ricevis avizon pri la hejtado.

is the normal and clear version.

You might omit ni in very informal situations, notes, or diary-like writing, but learners should generally include it. Esperanto verbs do not change according to the subject, so ricevis by itself does not tell you whether it means I received, we received, they received, etc.

A rough pronunciation guide is:

Nee ree-TSAY-vees ah-VEE-zon PREE lah hay-TAH-doh

A few helpful points:

• c is pronounced like ts
• j sounds like English y
• e is like e in bet, but often a bit clearer
• stress is always on the second-to-last syllable

So:

• ricevis → ri-CE-vis
• avizon → a-VI-zon
• hejtado → hej-TA-do