Lex clara est, et omnes sciunt iura civium servanda esse.

Because clara is an adjective describing lex, and est is the verb is.

• lex = law
• clara = clear
• est = is

So Lex clara est literally means The law is clear.

Notice that clara is feminine singular nominative because it agrees with lex, which is a feminine singular noun.

Because Latin adjectives must agree with the noun they describe in:

• gender
• number
• case

Here:

• lex is feminine
• lex is singular
• lex is nominative because it is the subject

So the adjective must also be feminine singular nominative: clara.

A learner coming from English often expects adjectives not to change, but in Latin they do.

Omnes means all or everyone here.

It can stand by itself without a noun. Latin often does this when the noun is easy to understand from context. So omnes sciunt means:

• all know
• or more naturally, everyone knows

Grammatically, omnes is nominative plural, functioning as the subject of sciunt.

Because its subject is omnes, which is plural.

• omnes = all people / everyone
• sciunt = they know

So the verb must also be plural.

This is different from English everyone knows, where we use a singular verb. Latin is following the plural form of omnes.

Because iura is the subject of an infinitive clause, not of the main verb.

After verbs like sciunt (they know), Latin often uses an accusative + infinitive construction for indirect statement. So instead of saying something like they know that the rights..., Latin says literally:

• they know the rights to-be-preserved to be

In this construction:

• iura is accusative because it is the subject of the infinitive esse
• the whole phrase iura civium servanda esse is what omnes sciunt

So iura is not the direct object of sciunt in the ordinary sense; it is the accusative subject of the indirect statement.

Iura is the neuter plural of ius, meaning right, law, or legal right depending on context.

Here it means rights.

A very common point for learners is that neuter plural nouns often end in -a, which can look singular if you are used to first-declension feminine nouns. But iura is definitely plural:

• singular: ius
• plural: iura

So iura civium means the rights of the citizens.

Civium is genitive plural.

It comes from civis, meaning citizen. The genitive here shows possession or belonging:

• iura civium = the rights of the citizens

So:

• iura = rights
• civium = of the citizens

English usually uses of for this idea, while Latin often uses the genitive case instead.

Servanda is a gerundive, often called the future passive participle. In this sentence it expresses necessity or obligation.

It comes from servo, servare = to preserve, to protect, to keep.

The ending -a is there because servanda agrees with iura, which is:

• neuter
• plural
• accusative

For neuter plural nominative or accusative, the gerundive takes -a:

• iura servanda = rights that must be preserved

So servanda means something like:

• to be preserved
• needing to be preserved
• must be preserved

Because the clause is an indirect statement after sciunt.

Latin normally uses:

• accusative subject
• • infinitive verb

So the infinitive esse is needed to complete the clause:

• iura civium servanda esse

Literally: that the rights of the citizens are to be preserved

If this were a main statement, Latin might say something like iura civium servanda sunt. But after sciunt, the finite verb becomes an infinitive:

• main statement: servanda sunt
• indirect statement: servanda esse

No. It does not mean ordinary passive action in progress.

Servanda esse expresses necessity, duty, or what ought to happen. So it means:

• must be preserved
• should be preserved
• are to be preserved

That is an important difference.

Compare:

• servantur = they are preserved
• servanda sunt / servanda esse = they must be preserved

Yes.

After verbs of saying, thinking, knowing, hearing, and perceiving, Latin often uses an indirect statement made of:

• an accusative subject
• an infinitive

Here:

• sciunt = they know
• iura = accusative subject of the infinitive
• esse = infinitive
• servanda = predicate adjective/gerundive agreeing with iura

So the whole clause iura civium servanda esse means that the rights of the citizens must be preserved.

This is one of the most important Latin constructions for English speakers to learn.

Because Latin word order is more flexible than English word order.

English depends heavily on position:

• The law is clear, and everyone knows that the rights of the citizens must be preserved.

Latin depends much more on endings. So words can move around without changing the basic grammar.

In this sentence, the order is quite natural Latin:

• Lex clara est
• et omnes sciunt
• iura civium servanda esse

The endings tell you the relationships:

• lex is the subject
• clara agrees with it
• omnes is the subject of sciunt
• iura is the accusative subject of esse
• civium is genitive
• servanda agrees with iura

So even if the order feels unusual to an English speaker, the grammar is clear from the forms.

A very literal translation of et omnes sciunt iura civium servanda esse would be:

and all know the rights of the citizens to be needing to be preserved

That is awkward English, but it helps show the Latin structure.

A better natural translation is:

and everyone knows that the rights of the citizens must be preserved

So the literal wording and the natural English wording are different, even though the meaning is the same.