La terapiisto kontrolas la ekvilibron kaj la sintenon.

The -n ending marks the direct object in Esperanto. These are the things being checked:

• La terapiisto = the therapist
• kontrolas = checks
• la ekvilibron = the balance
• kaj la sintenon = and the posture/attitude

So the therapist is doing the action, and balance and posture/attitude are receiving the action, which is why they take -n.

Because -as is the Esperanto ending for the present tense.

Some basic verb endings are:

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

So:

• kontrolas = checks / is checking
• kontrolis = checked
• kontrolos = will check

Esperanto often repeats la when it applies to two separate nouns:

• la ekvilibron kaj la sintenon

This makes it clear that both nouns are definite: the balance and the posture/attitude.

You may sometimes see a single la before coordinated nouns, but repeating it is very normal and often clearer, especially when the nouns are distinct items rather than a tightly linked pair.

Esperanto words are often built from parts:

• terapi- = therapy
• -ist- = a person professionally involved in something
• -o = noun ending

So terapiisto literally means a therapy professional, i.e. therapist.

This is very typical Esperanto word-building. Compare:

• piano = piano
• pianisto = pianist
• arto = art
• artisto = artist

It is a borrowing/international root, but that is completely normal in Esperanto. Many Esperanto words are based on roots that are recognizable from European languages, especially when they are widely international.

So kontroli is built and used like any ordinary Esperanto verb:

• kontroli = to check / to inspect / to verify
• kontrolas = checks
• kontrolis = checked

Even if a word looks familiar to an English speaker, it still follows Esperanto grammar regularly.

Usually yes, it is very similar. Ekvilibro can refer to:

• physical balance
• stability
• equilibrium

In a medical or therapy context, it most naturally means physical balance.

So in this sentence, la ekvilibron most likely refers to the patient’s ability to remain steady or balanced.

It can mean either, depending on context.

Common meanings of sinteno include:

• attitude
• bearing
• posture
• stance

In everyday abstract contexts, it often means attitude.
But in a therapy or medical setting, it can very naturally mean posture or body position.

So here, because the sentence is about a therapist checking things, posture is likely the intended sense.

Yes. Esperanto word order is fairly flexible because grammar is shown by endings, especially the -n object ending.

The normal, neutral order is:

• subject + verb + object

So:

• La terapiisto kontrolas la ekvilibron kaj la sintenon.

But other orders are possible for emphasis, such as:

• La ekvilibron kaj la sintenon kontrolas la terapiisto.

That still means the same thing because ekvilibron and sintenon have -n, showing they are objects.

Yes. Kaj simply means and, and it can join nouns, verbs, adjectives, clauses, and more.

Here it joins two direct objects:

• la ekvilibron
• la sintenon

Since both are direct objects, both keep the -n ending:

• la ekvilibron kaj la sintenon

That is exactly what you would expect in Esperanto.

Because terapiisto is the subject, not the object.

• La terapiisto = the one doing the action
• la ekvilibron kaj la sintenon = the things being acted on

Only the direct object gets -n here. So:

• La terapiisto kontrolas... = The therapist checks...
• not La terapiiston kontrolas..., which would mean something like Someone checks the therapist

Esperanto pronunciation is very regular. A rough guide:

• La = lah
• terapiisto = teh-rah-pee-EE-sto
• kontrolas = kon-TRO-lahs
• la = lah
• ekvilibron = ek-vee-LEE-bron
• kaj = kai
• la = lah
• sintenon = sin-TE-nohn

A few useful pronunciation points:

• Stress is always on the second-to-last syllable.
• j is pronounced like English y.
• Each vowel is pronounced clearly.

So kaj sounds like kai, not like English cage or kay.

Yes, depending on the intended meaning.

• La terapiisto kontrolas la ekvilibron kaj la sintenon.
  = The therapist checks the balance and the posture/attitude.

If you remove la, it becomes more general or indefinite:

• Terapiisto kontrolas ekvilibron kaj sintenon.

That might mean something more like A therapist checks balance and posture, or it may sound less natural if you mean a specific situation.

In most ordinary contexts, if you are talking about a particular therapist and specific things being examined, keeping la is the most natural choice.