Ju pli ni laboras laŭ simplaj reguloj, des pli granda estas nia progreso.

This is a very common Esperanto pattern meaning the more ... the more ..., the more ... the greater ..., and so on.

So:

• Ju pli ni laboras ... = The more we work ...
• des pli granda estas nia progreso = the greater our progress is

A good way to remember it:

• ju introduces the first side of the comparison
• des introduces the matching result

This pattern is specifically for proportional comparison.

More examples:

• Ju pli mi legas, des pli mi komprenas. = The more I read, the more I understand.
• Ju malpli vi dormas, des pli laca vi estas. = The less you sleep, the more tired you are.

Pli means more.

In this sentence, it appears twice because both halves are comparative:

• Ju pli ni laboras = the more we work
• des pli granda = the more great / the greater

In Esperanto, pli is used for comparison with adjectives, adverbs, and sometimes the idea of quantity or degree.

Examples:

• pli granda = bigger / greater
• pli rapide = more quickly
• pli labori = to work more

So here:

• first pli modifies the action laboras
• second pli modifies the adjective granda

Because standard Esperanto uses the pair ju ... des ....

English uses the ... the ..., but Esperanto does not repeat the same word. Instead, it uses:

• ju for the first clause
• des for the second clause

So:

• Ju pli ..., des pli ...

not normally:

• Ju pli ..., ju pli ...

If you are learning the pattern, it is best to memorize it as a fixed pair.

Laŭ usually means according to, in accordance with, or following.

So laŭ simplaj reguloj means something like:

• according to simple rules
• in accordance with simple rules
• by following simple rules

In this sentence, it tells us the way the work is being done: the work is done according to simple rules.

A few similar examples:

• Laŭ la leĝo = according to the law
• Laŭ mia opinio = in my opinion / according to me
• Ni agis laŭ plano. = We acted according to the plan.

Because adjectives in Esperanto must agree with the nouns they describe.

Here:

• reguloj = rules
• the ending -j shows plural
• so the adjective must also be plural: simplaj

That is why we get:

• simplaj reguloj = simple rules

Agreement in Esperanto:

• singular noun: simpla regulo
• plural noun: simplaj reguloj

If the noun were accusative too, the adjective would match that as well:

• simplan regulon
• simplajn regulojn

Because granda is a predicate adjective after estas, not a direct object.

In the second clause:

• nia progreso is the subject
• estas is the verb
• granda describes the subject

So granda stays in the basic adjective form.

Compare:

• Nia progreso estas granda. = Our progress is great.

But with a direct object, you would use -n:

• Ni vidas grandan domon. = We see a big house.

So in your sentence, pli granda is correct because it is linked to nia progreso through estas.

Because nia progreso is the subject of estas, not the object of a verb.

The structure is basically:

• nia progreso estas des pli granda

Even though the word order is a little different, nia progreso is still the thing being described, so it is the subject.

No direct object is present in that part, so there is no -n ending.

A more straightforward word order would be:

• Ju pli ni laboras laŭ simplaj reguloj, des pli granda nia progreso estas.
• or ..., des pli granda estas nia progreso.

In both cases, nia progreso is still the subject.

Esperanto word order is fairly flexible.

The sentence puts des pli granda first to emphasize the comparative result:

• des pli granda = the greater

Then comes:

• estas
• nia progreso

So the order highlights the idea of increasing greatness.

A more neutral order could be:

• Ju pli ni laboras laŭ simplaj reguloj, des pli granda nia progreso estas.

or even:

• Ju pli ni laboras laŭ simplaj reguloj, nia progreso estas des pli granda.

The original version sounds natural and stylistically good. Fronting the predicate like this is common in Esperanto.

Literally, granda often means big or large, but in many contexts it can also mean great.

With progreso, English usually prefers great or greater rather than big:

• granda progreso = great progress
• pli granda progreso = greater progress

So the Esperanto word is the same, but the best English translation depends on context.

This is normal in Esperanto: one word may cover a range that English splits into several words.

Progreso means progress in the general sense, and that fits this sentence well.

It refers to the amount or degree of progress being made, not to a specific act of progressing.

Progresado would emphasize the ongoing process of progressing, while progreso usually refers more naturally to the result or state of advancement.

So:

• nia progreso = our progress

is the most natural choice here.

Not exactly word-for-word, but it can often be translated that way depending on context.

Literally:

• ju pli ni laboras = the more we work

In natural English, sometimes the more we work and the harder we work are close enough in meaning. But Esperanto here is talking about a greater amount or degree of working, not specifically intensity alone.

If you wanted to focus more clearly on intensity, you might say something different, such as using an adverb meaning more intensely or more hard-workingly, depending on the exact idea.

So the original sentence is broad and general: the more we work.

Yes. The ju ... des ... pattern is very standard, and the rest of the sentence is normal Esperanto.

What may feel unusual to an English speaker is mainly:

• the fixed pair ju ... des ...
• the flexible word order in des pli granda estas nia progreso
• the use of laŭ for according to / following

But grammatically and stylistically, the sentence is quite natural.

It is a good example of how Esperanto expresses proportional comparison clearly and compactly.