Ju pli mi praktikas Esperanton, des pli klare mi parolas ĝin.

It means the more ... the more ... or sometimes the more ... the less ..., depending on the sentence.

So:

• Ju pli mi praktikas Esperanton, des pli klare mi parolas ĝin.

means:

• The more I practice Esperanto, the more clearly I speak it.

A useful way to remember it:

• ju introduces the changing condition
• des introduces the matching result

This is a very common comparative pattern in Esperanto.

Because each half of the comparison needs it.

• ju pli = the more
• des pli = the more

In this sentence:

• Ju pli mi praktikas Esperanton = The more I practice Esperanto
• des pli klare mi parolas ĝin = the more clearly I speak it

You are comparing one increase with another increase: more practice → more clarity in speaking.

Because klare is an adverb, and here it describes how the speaking happens.

• parolas = speaks
• klare = clearly

So mi parolas ĝin klare means I speak it clearly.

If you used klara, that would be an adjective, which describes a noun, not a verb. For example:

• klara lingvo = a clear language
• Li estas klara = He is clear

But here we need something that modifies parolas, so the adverb klare is correct.

Because it is the direct object of praktikas.

In Esperanto, the direct object usually takes the accusative ending -n.

• mi praktikas Esperanton = I practice Esperanto

The thing being practiced is Esperanto, so it gets -n.

This is true even though Esperanto is a proper name. Proper nouns can also take -n when they are direct objects.

Ĝin means it, and it refers back to Esperanton.

So:

• mi parolas ĝin = I speak it

The pronoun is used so you do not have to repeat Esperanton again. Esperanto often avoids unnecessary repetition this way, just like English does.

Also, ĝin has -n because it is the direct object of parolas.

Yes, it could:

• Ju pli mi praktikas Esperanton, des pli klare mi parolas Esperanton.

That is grammatically fine, but it sounds more repetitive. Using ĝin is more natural and smoother.

So both are correct, but ĝin is usually better style here.

Because praktiki can be used transitively, meaning to practice something.

So:

• praktiki Esperanton = to practice Esperanto

That is a normal and natural way to say it.

If you said something with en Esperanto, that would shift the meaning more toward doing something in Esperanto, not necessarily practicing the language itself.

For example:

• Mi skribas en Esperanto. = I write in Esperanto.
• Mi praktikas Esperanton. = I practice Esperanto.

Those are related ideas, but not the same.

Esperanto word order is fairly flexible, but some patterns sound more standard and elegant than others.

In comparative correlation structures, des pli is commonly placed together near the front of its clause:

• des pli klare mi parolas ĝin

This makes the comparison very clear and easy to follow.

You may sometimes see slightly different word orders, but keeping des pli together is the most straightforward choice.

No. Even though ju may look unfamiliar, it is not asking a question.

In this sentence, ju is part of the fixed comparison pattern ju ... des ....

So here it does not mean how? or anything like that. It simply marks the first half of a proportional comparison:

• ju pli = the more
• ju malpli = the less

Examples:

• Ju pli mi legas, des pli mi komprenas. = The more I read, the more I understand.
• Ju malpli vi rapidas, des malpli vi eraras. = The less you hurry, the fewer mistakes you make.

Yes. The pattern is ju ... des ..., and the compared words can vary.

For example:

• Ju pli ..., des pli ... = the more ..., the more ...
• Ju malpli ..., des malpli ... = the less ..., the less ...
• Ju pli ..., des malpli ... = the more ..., the less ...

Examples:

• Ju pli mi lernas, des pli mi scias. = The more I learn, the more I know.
• Ju pli mi laboras, des malpli mi ripozas. = The more I work, the less I rest.

So pli is common, but it is not the only possibility.

Yes. The ju ... des ... structure is not limited to the present tense.

This sentence uses the present:

• mi praktikas
• mi parolas

But you could use past or future too, depending on the meaning.

For example:

• Ju pli mi praktikis Esperanton, des pli klare mi parolis ĝin. = The more I practiced Esperanto, the more clearly I spoke it.
• Ju pli mi praktikos Esperanton, des pli klare mi parolos ĝin. = The more I will practice Esperanto, the more clearly I will speak it.

So the structure stays the same; only the verb tense changes.

Because Esperanto is a proper name, and Esperanto normally does not use la with proper names like this.

So:

• mi praktikas Esperanton = I practice Esperanto

not normally:

• mi praktikas la Esperanton

Using la here would sound unusual unless you had some very specific special meaning.

Not completely, but it is very close.

The general meaning matches English very well:

• The more I practice Esperanto, the more clearly I speak it.

But some details work differently:

• Esperanto uses -n for direct objects: Esperanton, ĝin
• Esperanto uses the fixed pair ju ... des ...
• Esperanto clearly marks adverbs with -e: klare

So the sentence is easy for an English speaker to understand, but it also shows some important Esperanto grammar features.