La dentrado kaj la pedalo funkcias kune.

La is the Esperanto definite article, the equivalent of the. It does not change for gender, number, or case.

In this sentence, both nouns are definite, so la is repeated before each one:

la dentrado kaj la pedalo

That is the clearest and most natural beginner-friendly pattern. In some contexts, Esperanto can omit a repeated article, but if you want to be safe and clear, use la with each definite noun.

Because -o is the normal noun ending in Esperanto.

So:

• dentrado = a noun
• pedalo = a noun

This is one of the most basic patterns in Esperanto:

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

If these nouns were plural, they would end in -oj:

• dentradoj
• pedaloj

Dentrado is a compound word.

It is built from:

• dent- = tooth
• rad- = wheel
• -o = noun ending

So literally it is something like tooth-wheel, which gives the idea of a gear or cogwheel.

A useful Esperanto pattern is that compound words often combine roots directly, with the main idea at the end.

The base verb is funkcii, meaning to function or to work.

The ending -as marks the present tense:

• funkcii = to function
• funkcias = functions / is functioning / work(s)

So La dentrado kaj la pedalo funkcias kune means that the gear and the pedal are functioning together now.

Because Esperanto verbs do not change for person or number.

English changes:

• the pedal works
• the gear and the pedal work

Esperanto does not do that. The present tense is always -as:

• la pedalo funkcias
• la dentrado kaj la pedalo funkcias
• mi funkcias
• ili funkcias

So even with a plural subject, the verb stays funkcias.

Because there is no direct object here.

In this sentence, la dentrado kaj la pedalo is the subject: they are the things performing the action.

The accusative -n is usually used for a direct object, for example:

• La dentrado movas la pedalon.

Here la pedalon has -n because it is the thing being moved.

But in La dentrado kaj la pedalo funkcias kune, nothing is receiving the action, so no accusative is needed.

Because kune is an adverb meaning together, while kun is a preposition meaning with.

Here, kune describes how they function:

• funkcias kune = function together

If you used kun, it would need its own noun or pronoun:

• La pedalo funkcias kun la dentrado. = The pedal functions with the gear.

That sentence is possible, but it is structured differently. In your sentence, kune is the right choice because it expresses the idea of doing something jointly.

Yes, to some extent. Esperanto word order is fairly flexible.

The given sentence has a neutral, straightforward order:

La dentrado kaj la pedalo funkcias kune.

You could also see variations such as:

• Kune funkcias la dentrado kaj la pedalo.
• La pedalo kaj la dentrado funkcias kune.

These may shift emphasis slightly, but the original version is the most neutral and easiest for a learner to recognize.

No. Funkcii is often used for machines, systems, or body parts, but it can also be used more generally for something that works, functions, or operates.

So in this sentence it fits well, because dentrado and pedalo are parts that operate together.

Depending on context, English might translate it as:

• function together
• work together
• operate together

All of those are close in meaning here.