Ni kolektas monon por la komunumo.

Because monon has the -n ending of the accusative, which usually marks the direct object in Esperanto.

In Ni kolektas monon por la komunumo, the thing being collected is money, so mono becomes monon.

• mono = money
• monon = money as the direct object

This is one of the most important endings in Esperanto:

• La hundo vidas la katon = The dog sees the cat.
• La kato vidas la hundon = The cat sees the dog.

The -n helps show what receives the action.

Because la komunumo is not the direct object here. It is part of the prepositional phrase por la komunumo.

• por = for
• por la komunumo = for the community

After a preposition like por, the noun normally does not take -n unless there is a special reason involving direction or movement, and that is not the case here.

So:

• monon = direct object
• por la komunumo = prepositional phrase showing purpose/beneficiary

Ni means we. By itself, it does not specify whether it includes the listener or not.

So Esperanto ni can correspond to either:

• we including you
• we excluding you

Usually the context makes it clear. Esperanto does not normally make a grammatical distinction there.

In Esperanto, -as marks the present tense.

So:

• kolekti = to collect
• kolektas = collect / are collecting

Other common verb endings are:

• -is = past
• -os = future
• -us = conditional
• -u = command/jussive
• -i = infinitive

Examples:

• Ni kolektas monon = We collect / are collecting money
• Ni kolektis monon = We collected money
• Ni kolektos monon = We will collect money

It can mean either, depending on context.

Esperanto present tense does not force a distinction like English often does. So Ni kolektas monon may mean:

• We collect money
• We are collecting money

If the context makes it ongoing right now, English often prefers are collecting. If it is more general or habitual, English may prefer collect.

La is the definite article, meaning the.

So:

• komunumo = community
• la komunumo = the community

You use la when the noun is definite, just like English the. In this sentence, it refers to a specific community known from context.

A few useful points:

• Esperanto has only one definite article: la
• It does not change for number or gender
• There is no indefinite article equivalent to English a/an

So:

• komunumo = a community / community
• la komunumo = the community

Esperanto often leaves that idea unexpressed when it is not necessary.

Monon by itself can naturally mean money in a general sense, and in English that may be translated as:

• money
• some money

Because money is an uncountable noun, Esperanto does not need an extra word here.

If you wanted to be more specific, you could say:

• iom da mono = some money, a certain amount of money

But Ni kolektas monon is completely normal.

No, not in standard Esperanto.

Because money is the direct object of collect, it needs the accusative -n:

• correct: Ni kolektas monon
• incorrect: Ni kolektas mono

The noun form itself is mono, but when it functions as the direct object, it becomes monon.

Here por means for in the sense of for the benefit of or intended for.

So por la komunumo means for the community.

It is not the same as pro.

• por = for, intended for, for the sake of, in order to
• pro = because of, due to

Compare:

• Ni kolektas monon por la komunumo. = We are collecting money for the community.
• Ni restis hejme pro la pluvo. = We stayed home because of the rain.

English speakers often mix these up at first.

Yes, Esperanto word order is fairly flexible, partly because the accusative -n helps show grammatical function.

The neutral order is:

• Ni kolektas monon por la komunumo.

But other orders are possible, for example:

• Monon ni kolektas por la komunumo.
• Por la komunumo ni kolektas monon.

These alternatives may add emphasis or change the focus slightly, but the basic meaning stays the same.

Still, for learners, the most natural default is usually: subject + verb + object + other phrases

Komunumo is singular: community.

To make it plural, add -j:

• komunumo = community
• komunumoj = communities

So:

• por la komunumo = for the community
• por la komunumoj = for the communities

Notice that la stays the same.

Because plural nouns in Esperanto take -j.

Here are the forms:

• mono = money
• monoj = monies / types of money, or separate sums in special contexts
• monon = money as a direct object
• monojn = plural direct object

In this sentence, monon has only -n, not -j, so it is not plural.

Also, with a mass noun like money, singular is usually what you want.

A simple approximate pronunciation is:

Nee ko-LEK-tahs MOH-nohn por lah ko-moo-NOO-moh

A few helpful points:

• Ni sounds like nee
• kolektas has stress on LEK
• monon has stress on the first mo
• komunumo has stress on nu

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

• ko-LEK-tas
• MO-non
• ko-mu-NU-mo

Also, Esperanto spelling is very regular, so pronunciation is much more predictable than in English.