Grupo de infanoj kultivas plantojn.

These are some of the most important Esperanto endings:

• -o = a noun
• -j = plural
• -n = direct object

So in this sentence:

• grupo = grup- + -o = group
• infanoj = infan- + -o + -j = children
• plantojn = plant- + -o + -j + -n = plants as the direct object

This kind of stacking is very normal in Esperanto.

Because grupo is the main noun, and it is singular: it means one group.

The phrase de infanoj just tells you what the group consists of. So the structure is:

• grupo = the main thing
• de infanoj = of children

So the sentence talks about one group, made up of many children.

Because plantojn is the direct object of kultivas.

In other words, it is the thing being cultivated. Esperanto marks direct objects with -n.

• Grupo de infanoj kultivas plantojn.
• The group is doing the action.
• The plants are receiving the action.

That is why plantoj becomes plantojn.

Because infanoj is not the direct object.

It comes after the preposition de, and in normal Esperanto, nouns after prepositions usually do not take the direct-object ending.

So:

• de infanoj = of children
• plantojn = the direct object

Only plantojn gets -n here.

De usually means of, from, or sometimes shows relationship.

Here it means of:

• grupo de infanoj = a group of children

It tells you what kind of group it is, or what the group is made up of.

The ending -as shows the present tense.

So:

• kultivi = to cultivate
• kultivas = cultivates / are cultivating / cultivate

Esperanto present tense is often broader than English. Depending on context, kultivas can correspond to English cultivates, cultivate, or is/are cultivating.

The dictionary form is kultivi.

In Esperanto, verbs are usually listed in the infinitive, which ends in -i.

So:

• kultivi = to cultivate
• stem: kultiv-
• kultivas = present tense
• kultivis = past tense
• kultivos = future tense

No. Esperanto verbs do not agree with the subject in number or person.

So all of these use kultivas:

• mi kultivas = I cultivate
• li kultivas = he cultivates
• ili kultivas = they cultivate
• grupo kultivas = a group cultivates

This is much simpler than English.

Because Esperanto has no indefinite article.

English has:

• a group
• the group

Esperanto only has la for the. There is no separate word for a/an.

So:

• grupo = a group or just group, depending on context
• la grupo = the group

In this sentence, grupo naturally means a group.

Not completely, but the normal order here is the most natural one:

• Grupo de infanoj kultivas plantojn.

That is a standard subject–verb–object order.

Because Esperanto marks the direct object with -n, the order can be changed more freely than in English. For example:

• Plantojn kultivas grupo de infanoj.

This is still grammatical, because plantojn is clearly marked as the object. But for learners, the basic order is the best one to use first.

Yes, and it would be perfectly grammatical.

But the focus changes a little:

• Grupo de infanoj kultivas plantojn = a group of children is doing it
• Infanoj kultivas plantojn = children are doing it

The second version is more general. The original sentence specifically mentions them as a group.

You may hear both, but grupo de infanoj is the safest and most straightforward choice here.

Why?

• de is the normal way to show a group of children
• da is mainly used with quantities, amounts, and measures

Some speakers use grupo da infanoj, especially when they are thinking of the children more as a quantity or crowd. But for a learner, grupo de infanoj is an excellent default.

A simple approximation is:

• infanoj ≈ in-FA-noy
• plantojn ≈ PLAN-toyn

A few helpful pronunciation points:

• j sounds like English y
• oj sounds like oy
• stress in Esperanto is always on the second-to-last syllable

So:

• gru-po → GRU-po
• in-fa-noj → in-FA-noy
• kul-ti-vas → kul-TI-vas
• plan-tojn → PLAN-toyn