Senatus hodie in curia sedet, et praetor ante ostium quietem servari iubet.

Latin has no articles, so it does not have separate words for the or a/an.

That means:

• senatus = the senate or a senate, depending on context
• curia = the senate-house / the council chamber
• praetor = the praetor
• ostium = the door / entrance

In a sentence like this, English normally uses the because the people and places are understood as specific.

Senatus is singular here. It means the senate as one body.

Even though a senate is made up of many people, Latin treats senatus as a singular noun, just as English often does with the government, the committee, or the team.

A useful extra point: senatus is a 4th-declension noun, so its -us ending does not make it 2nd declension.

Because senatus is in the nominative singular, and sedet is 3rd person singular.

So the first clause is structured as:

• Senatus = subject
• hodie = adverb
• in curia = place
• sedet = verb

The endings and forms tell you who is doing the action, even though the word order is not exactly like English.

Literally, sedet means sits or is sitting.

But in this context, with senatus, it often has the more natural sense:

• is in session
• is sitting officially
• is meeting

So Latin uses a very ordinary verb, to sit, in a political setting where English may prefer something like meets or is in session.

Because in can take two different cases:

• in + ablative = in / on a place, with location
• in + accusative = into / onto a place, with motion toward

Here the senate is already in the building, not moving into it, so Latin uses the ablative:

• in curia = in the senate-house

If it meant into the senate-house, you would expect in curiam.

It is ablative singular.

That is because it follows in in the sense of location:

• in curia = in the senate-house

So this is a very common prepositional phrase: preposition + ablative for place where something happens.

Hodie is an adverb meaning today.

Latin adverbs often have fairly flexible placement. Here it appears early because it sets the scene right away:

• Senatus hodie in curia sedet
  = Today the senate is sitting in the senate-house

Putting hodie near the front gives time-information immediately, which is very natural in Latin.

Ostium is accusative singular because ante takes the accusative.

So:

• ante ostium = before the door / in front of the entrance

This is just how the preposition works. Even though English does not show a case ending here, Latin does.

Praetor is in the nominative singular, and iubet is 3rd person singular, so they match.

In the second clause:

• praetor = subject
• ante ostium = where he is
• quietem servari = what he orders
• iubet = main verb

So the structure is: the praetor orders ...

The verb iubeo (order, command) commonly takes an infinitive construction rather than an ut-clause.

So instead of saying something exactly like:

• he orders that quiet be kept

Latin says:

• he orders quiet to be kept
• quietem servari iubet

This is very normal Latin with iubeo.

Because it is the subject of the infinitive servari in an accusative-and-infinitive-type construction after iubet.

So:

• quietem = quiet, in the accusative
• servari = to be kept

Together:

• quietem servari = quiet to be kept / that quiet be kept

Even though English would not usually phrase it this way, Latin regularly uses the accusative as the logical subject of an infinitive.

Servari is the present passive infinitive of servo, servare.

So:

• servare = to keep
• servari = to be kept

That is why quietem servari means quiet to be kept or more naturally that quiet be maintained.

The passive lets Latin express the command without naming who must do it.

So:

• quietem servari iubet = he orders that quiet be kept

This focuses on the result wanted—the maintenance of quiet—rather than on the people who must obey.

If Latin used an active form, it would more naturally need to specify who is to do the keeping.

Exactly: Latin leaves that unspecified.

The meaning is general:

• the people nearby
• those at the door
• the crowd
• anyone present

The praetor is giving a command that applies to the situation as a whole. The passive infinitive is useful because it allows Latin to say what must happen without naming the doers.

Latin word order is much freer than English word order because Latin uses case endings and verb forms to show grammatical relationships.

For example:

• Senatus is the subject because of its form
• curia is ablative because of in
• quietem is accusative
• servari is an infinitive
• iubet is the main verb

Because of that, Latin can arrange words for emphasis, rhythm, or style, not just for grammatical clarity.

A few features here are especially common:

• time word early: hodie
• place before verb: in curia
• main verb often near the end: iubet

So the sentence is not strange Latin at all; it is quite natural.