Quam celeriter siparium cadit!

Here quam means how in an exclamation: How quickly...!

It is not the comparative than here. Latin often uses quam + adjective/adverb to make an exclamation:

• quam pulcher! = how beautiful!
• quam celeriter! = how quickly!

So quam is intensifying celeriter.

Because celeriter is an adverb, and it modifies the verb cadit.

• celer = swift, quick (an adjective)
• celeriter = quickly, swiftly (an adverb)

Since the sentence is describing how the curtain falls, Latin uses the adverb:

• cadit = falls
• celeriter cadit = falls quickly

It comes from the adjective celer, celeris, celere.

A very common way to form an adverb from a 3rd-declension adjective is to add -iter:

• celer → celeriter

So this is a normal adverb formation meaning quickly or swiftly.

Siparium is nominative singular neuter.

It is the subject of cadit, so it is in the nominative case:

• siparium = the curtain
• cadit = falls

So siparium cadit means the curtain falls.

Siparium is a noun, and it is a 2nd-declension neuter noun.

Its basic forms would be:

• nominative singular: siparium
• genitive singular: siparii

It means a curtain or stage curtain/backdrop, so it is a somewhat theatrical word rather than the most everyday vocabulary.

Cadit is:

• 3rd person singular
• present tense
• active voice
• indicative mood

It comes from cadere, meaning to fall.

Because the subject siparium is singular, the verb is singular too:

• siparium cadit = the curtain falls

Latin does not have definite or indefinite articles like English the or a/an.

So siparium can mean:

• a curtain
• the curtain

The context tells you which one is more natural. In this sentence, English usually says the curtain.

It is an exclamation.

The pattern quam + adverb/adjective is very commonly exclamatory, and the exclamation mark shows that clearly in modern editions:

• Quam celeriter siparium cadit!
• How quickly the curtain falls!

Without context, how quickly could look like the start of a question in English, but here it is expressing surprise or emotion, not asking for information.

Latin word order is flexible, and the first position is often used for emphasis.

Putting quam first gives the sentence an immediately exclamatory force:

• Quam celeriter... = How quickly...!

This is very natural Latin word order for an exclamation. The important emotional idea comes first.

Yes. Latin allows much more flexibility than English.

For example, the same basic meaning could still be understood in other arrangements, such as:

• Siparium quam celeriter cadit!
• Cadit quam celeriter siparium!

But the given order is the most natural for an exclamation because it foregrounds quam celeriter. Latin often uses word order to show emphasis, not just grammar.

Not always. Cadere literally means to fall, but in context it can also be understood as goes down, drops, or comes down.

With a curtain, English may translate it naturally as:

• the curtain falls
• the curtain comes down

So the Latin is literal, but the most idiomatic English may vary a little depending on context.