Mi volas diri ion al vi.

Here is the breakdown:

• Mi = I
• volas = want
• diri = to say
• ion = something
• al = to
• vi = you

So the structure is very close to English: I want to say something to you.

After a verb like voli (to want), the next verb stays in the infinitive form, which ends in -i.

So:

• volas = the main, conjugated verb: want
• diri = infinitive: to say

This works like English want to say.

Examples:

• Mi volas iri. = I want to go.
• Ŝi volas manĝi. = She wants to eat.

You do not say volas diras, because Esperanto does not use two fully conjugated verbs there.

The -n marks the direct object.

In this sentence, ion is the thing being said: something. That makes it the direct object of diri.

Compare:

• io = something as a basic form
• ion = something as a direct object

This is a very common Esperanto pattern:

• Mi vidas hundon. = I see a dog.
• Li manĝas pomon. = He is eating an apple.

So ion has -n because it receives the action of diri.

Because vi is not the direct object here. It is the person the speech is directed to, so Esperanto uses the preposition al.

• ion = the thing being said
• al vi = to you

So:

• diri ion al vi = say something to you

If you used vin, that would make you the direct object, which would mean something different or sound wrong here.

A useful comparison:

• Mi vidas vin. = I see you.
  Here vin is the direct object.
• Mi parolas al vi. = I am speaking to you.
  Here al vi shows direction toward the listener.

In Esperanto, the infinitive verb ending -i already includes the idea of English to.

So:

• diri = to say
• iri = to go
• fari = to do / to make

You do not add a separate word for to before the infinitive.

Yes, Esperanto word order is fairly flexible, because endings and prepositions show the grammar clearly.

For example, these are all understandable:

• Mi volas diri ion al vi.
• Mi volas diri al vi ion.

Both mean essentially the same thing.

However, Mi volas diri ion al vi is a very natural, straightforward order. For learners, it is usually best to start with this kind of simple word order.

This is a very common question.

• diri = to say, to tell, focusing on the actual words or message
• paroli = to speak, focusing more on the act of speaking

So:

• Mi volas diri ion al vi. = I want to say something to you.
• Mi volas paroli al vi. = I want to speak to you.

If you specifically mean there is a particular thing you want to say, diri ion is the better choice.

Because io is the basic form, but in this sentence the word is the direct object, so it becomes ion.

Think of it like this:

• Io estas sur la tablo. = Something is on the table.
  Here io is the subject.
• Mi vidas ion. = I see something.
  Here ion is the direct object.

In your sentence, the speaker wants to say something, so that word must take -n.

Vi can mean either you singular or you plural.

So it can mean:

• you = one person
• you all / you people = more than one person

Esperanto normally uses the same pronoun for both, just like modern English usually does.

Yes. In Esperanto, -as is the present tense ending.

So:

• volas = want / am wanting
• diras = say / am saying
• iras = go / am going

Esperanto present tense is often broader than English tense labels suggest. In practice, Mi volas diri ion al vi is simply the normal way to say I want to say something to you.

Yes, very naturally.

Esperanto diri often corresponds to English say, but in real use English might translate it as tell depending on the context.

So Mi volas diri ion al vi can be understood as:

• I want to say something to you
• I want to tell you something

Both are good English translations, depending on tone and situation.