Quo maior superbia est, eo difficilius veritas dicitur.

It is a standard Latin correlative comparative construction, used for English the ... the ... statements:

• quo maior superbia est = the greater the pride is
• eo difficilius veritas dicitur = the more difficultly truth is spoken

More literally, quo and eo mean something like by which amount and by that amount, but in normal English we usually just translate the pattern as the more ..., the more ... or the greater ..., the more difficult ....

Both quo and eo are in the ablative, because this construction uses the ablative to express degree of difference.

No. That is a very common first guess, because quo can sometimes be connected with meanings like to where or whither in other contexts.

But here quo is not about place at all. In this sentence, it is part of the fixed comparative pattern quo ... eo ..., meaning the more ... the more ....

So here:

• quo maior superbia est does not mean where pride is greater
• it means the greater the pride is

Maior is the comparative form of magnus and means greater.

It agrees with superbia:

• superbia = feminine singular nominative
• maior = feminine singular nominative comparative

So maior superbia means greater pride.

Even though English often says more pride, Latin commonly uses the comparative adjective here: greater pride.

Because it is the subject of est.

In the first clause:

• superbia = subject
• est = is
• maior = predicate adjective describing superbia

So the structure is essentially:

• superbia est maior = pride is greater

Latin word order is flexible, so it appears as quo maior superbia est, but the grammar is the same.

Here difficilius is being used adverbially, not as an adjective agreeing with a noun.

It modifies dicitur, so it means:

• more difficultly
• or more naturally in English, with greater difficulty

This is why it does not agree with veritas.

A useful thing to remember is that the comparative adverb often has the same form as the neuter nominative/accusative singular of the comparative adjective. So difficilius here functions as an adverb:

• veritas difficilius dicitur = truth is spoken more difficultly / truth is spoken with more difficulty

Because veritas is the subject of the passive verb dicitur.

• dicitur = is said / is spoken
• so veritas dicitur = truth is said / truth is spoken

In an active sentence, truth might be the object, but in the passive it becomes the subject. That is why veritas is nominative.

Because Latin often uses the passive where English might prefer either:

• a passive: truth is spoken
• or an indefinite active: people speak the truth

So veritas dicitur literally means truth is said/spoken, with no need to mention who says it.

This gives the sentence a more general, proverbial tone. It is making a general statement, not describing one specific speaker.

Latin word order is much more flexible than English word order, because the endings show the grammatical relationships.

The sentence is arranged in two balanced parts:

• quo maior superbia est
• eo difficilius veritas dicitur

This puts the paired words quo ... eo and the two comparatives maior ... difficilius in prominent positions. That balance is stylistically neat and very natural in Latin.

If you rearranged the ideas more mechanically, you could think of it as:

• superbia quo maior est, veritas eo difficilius dicitur

But the original order is more elegant.

The present tense here expresses a general truth or gnomic statement.

Latin often uses the present for maxims, proverbs, and observations that are meant to be generally true:

• superbia est = pride is
• veritas dicitur = truth is spoken

So the sentence is not talking about one specific moment. It means something like a universal principle: when pride is greater, speaking the truth becomes harder.

Because Classical Latin has no definite article and no indefinite article.

So Latin can simply say:

• superbia = pride / the pride
• veritas = truth / the truth

English has to choose an article or leave it out depending on what sounds natural. Latin does not.

In this sentence, English normally uses abstract nouns without an article or with one depending on style:

• the greater the pride, the more difficult it is to speak the truth
• the greater pride is, the more difficultly truth is spoken

It can be understood as either, depending on how you phrase the English.

Latin veritas is an abstract noun, so it often means truth in a general sense. But in English, a natural translation may use the truth, because that sounds more idiomatic in this kind of sentence.

So the Latin itself does not force a sharp distinction here. The idea is simply that truth becomes harder to say when pride is greater.