La vespermanĝo estas bufedo.

Esperanto very often builds new words by compounding smaller ones into a single word.

• vesper- = evening
• manĝo = meal, eating

So vespermanĝo is literally evening-meal.

This is completely normal in Esperanto. The main idea usually comes at the end, so manĝo is the core noun, and vesper- tells what kind of meal it is.

Other similar examples:

• matenmanĝo = breakfast
• tagmanĝo = lunch / midday meal

The ending -o marks a noun in Esperanto.

So:

• vespermanĝo is a noun
• bufedo is also a noun

This is one of the most regular parts of Esperanto grammar:

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

Because both words are things or concepts, they end in -o.

La is the Esperanto definite article, equivalent to the in English.

So La vespermanĝo means the dinner rather than just dinner in a general sense.

Esperanto has only one article:

• la = the

There is no separate word for a or an in Esperanto.

So:

• La vespermanĝo = the dinner
• Vespermanĝo = dinner / a dinner / dinner in general, depending on context

In Esperanto, a predicate noun after estas often appears without an article, especially when it describes what something is.

So in:

• La vespermanĝo estas bufedo.

bufedo is not the object of the verb. It is a predicate noun, telling you what the dinner is.

This works a lot like English in sentences such as:

• John is a teacher.
• This is water.

Esperanto often leaves out an equivalent of a/an because Esperanto has no indefinite article.

If you said la bufedo, that would usually mean the buffet, referring to a specific buffet already known from context.

Estas is the present-tense form of esti, meaning to be.

So:

• esti = to be
• estas = is / are / am

Esperanto uses the same present-tense form for all persons:

• mi estas = I am
• vi estas = you are
• li estas = he is
• ili estas = they are

Here, estas links the subject La vespermanĝo with the description bufedo.

Because it is not a direct object.

The ending -n is usually used for:

• a direct object
• direction toward something in some cases

But after esti (to be), the noun that follows is a predicate noun, not an object.

So:

• La vespermanĝo estas bufedo. ✔
• La vespermanĝo estas bufedon. ✘

The same pattern appears in sentences like:

• Li estas kuracisto. = He is a doctor.
• Ŝi estas mia amiko. = She is my friend.

A rough pronunciation is:

VES-per-MAN-jo

A few helpful points:

• v sounds like English v
• e is like e in met, but clearer and steadier
• g is always hard, as in go
• ĝ sounds like English j in jam
• o is like a clear o, not a diphthong

So the last part -manĝo sounds roughly like MAN-jo.

Also, Esperanto stress normally falls on the second-to-last syllable:

• ves-per-MAN-ĝo

They are two different letters and two different sounds.

• g = hard g, as in go
• ĝ = j sound, as in judge

So in vespermanĝo, the ĝ is important. Without it, the word would be pronounced differently and would be a different spelling.

This is very typical in Esperanto: accented letters are separate letters, not optional decorations.

The normal, neutral order is:

• La vespermanĝo = subject
• estas = verb
• bufedo = predicate noun

So:

• La vespermanĝo estas bufedo.

That is the most straightforward version.

Esperanto word order is somewhat flexible, but this standard order is best for learners. Changing the order is possible in some contexts, but it may sound marked, poetic, or less natural unless there is a reason for emphasis.

It is basically a borrowed/international-style word, like many nouns in Esperanto.

Esperanto uses both:

• words built from roots already in the language
• words borrowed from widely known international vocabulary

So bufedo is a normal Esperanto noun, even though it comes from an international source. Once it is in Esperanto, it behaves like any other noun:

• bufedo = buffet
• bufedoj = buffets
• bufeda = buffet-related / buffet-style

Yes, in normal use that is often the practical meaning.

Grammatically, the sentence says:

• The dinner is a buffet.

In real-world context, that usually means:

• the meal is being served as a buffet
• dinner will be buffet-style

So even if the literal structure is noun = noun, the intended meaning is often about the format of the meal.

That kind of wording is common and understandable in Esperanto.