Mi preparas salaton kun tomatoj kaj cepoj por la tagmanĝo.

Because salaton is the direct object of the verb preparas.

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

• salato = a salad
• salaton = a salad, as the thing being prepared

In this sentence, the speaker is preparing the salad, so salaton gets -n.

Because they are not the direct object of the verb. They are part of the phrase kun tomatoj kaj cepoj = with tomatoes and onions.

The preposition kun means with, and nouns after a preposition normally do not take -n just because they follow that preposition.

So:

• kun tomatoj = with tomatoes
• kun cepoj = with onions

The thing being prepared is salaton, not tomatojn or cepojn.

The ending -as marks the present tense in Esperanto.

So:

• prepari = to prepare
• preparas = prepares / am preparing / is preparing / are preparing

Esperanto uses one present-tense form for all persons:

• mi preparas = I prepare / I am preparing
• vi preparas = you prepare / you are preparing
• li preparas = he prepares / he is preparing

Unlike English, the verb does not change depending on the subject.

In Esperanto, verbs do not change according to the subject.

That means:

• mi preparas
• vi preparas
• ŝi preparas
• ili preparas

all use the same present-tense ending -as.

This is much simpler than English, where we say I prepare but he prepares.

The ending -j marks the plural in Esperanto.

So:

• tomato = tomato

• tomatoj = tomatoes

• cepo = onion
• cepoj = onions

In Esperanto, plural is very regular: just add -j to the noun ending.

Kun means with.

It introduces something that accompanies something else. In this sentence:

• salaton kun tomatoj kaj cepoj = salad with tomatoes and onions

So kun connects the salad to its ingredients or accompanying items.

Por usually means for.

Here, por la tagmanĝo means for lunch or more literally for the lunch meal.

It shows purpose or intended use:

• Mi preparas salaton por la tagmanĝo. = I am preparing a salad for lunch.

So the salad is being prepared for that meal.

La is the definite article, meaning the.

So:

• tagmanĝo = lunch / a lunch meal
• la tagmanĝo = the lunch / lunch in a specific context

In many cases, Esperanto uses la where English might or might not use the, depending on context. Here it suggests a specific meal, such as today’s lunch or the lunch we have in mind.

Also, la never changes form. It is always just la, no matter whether the noun is singular, plural, subject, or object.

Because Esperanto often forms new words by combining meaningful parts.

tagmanĝo is made from:

• tag = day
• manĝo = meal, eating

Together, tagmanĝo means the meal of the day, that is, lunch.

This kind of compounding is very common in Esperanto, and it is one of the language’s most regular features.

Esperanto word order is fairly flexible, but the most common and neutral order is:

subject + verb + object

So:

• Mi preparas salaton ... = I am preparing a salad ...

Because salaton has the object ending -n, Esperanto can sometimes move things around more freely than English can. Still, the given order is the most natural one for a beginner to use.

The subject is mi, which means I.

In this sentence:

• Mi = subject
• preparas = verb
• salaton = direct object

A helpful clue is that the direct object has -n, while the subject normally does not. So mi is doing the action, and salaton is receiving it.

A rough pronunciation is tahg-MAHN-jo.

A few helpful points:

• g is a normal hard g
• ĝ sounds like the j in jam
• o is pronounced clearly, not reduced

So manĝo sounds roughly like MAHN-jo, and tagmanĝo keeps both parts together.

It most naturally refers to a specific lunch because of la tagmanĝo.

If someone wanted to speak more generally, context would help, and they might choose a slightly different phrasing. But as written, the sentence strongly suggests a particular lunch meal, not lunch in general as an abstract concept.

So a learner should read it as something like:

• I am preparing a salad with tomatoes and onions for the lunch meal.