Paries cubiculi albus est, sed paries atrii iam sordidus est.

Because they are in the genitive singular, which here means of the bedroom and of the atrium.

• cubiculum = bedroom
• cubiculi = of the bedroom
• atrium = atrium
• atrii = of the atrium

So:

• paries cubiculi = the wall of the bedroom
• paries atrii = the wall of the atrium

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

Yes, Latin could sometimes leave it out if the meaning were obvious, but repeating it makes the sentence clearer and more balanced.

So this sentence is structured as:

• Paries cubiculi albus est
• sed paries atrii iam sordidus est

Repeating paries helps emphasize the contrast between the two walls. It is a very natural way to say it.

Because they agree with paries, which is a masculine singular noun.

In Latin, adjectives must agree with the noun they describe in:

• gender
• number
• case

Here:

• paries is nominative singular masculine
• so albus must also be nominative singular masculine
• and sordidus must also be nominative singular masculine

Even though cubiculum and atrium are neuter, the adjectives are not describing those words. They are describing paries.

It is nominative singular.

That is because paries is the subject of each clause:

• Paries cubiculi albus est = The wall of the bedroom is white
• paries atrii iam sordidus est = the wall of the atrium is already dirty

The subject of est is in the nominative.

No. Here paries is singular.

This is a common point of confusion, because many Latin plurals do end in -es, especially in the third declension. But some singular nouns also end in -es.

For this noun:

• nominative singular: paries
• genitive singular: parietis
• nominative plural: parietes

So paries means wall, not walls.

Iam usually means now, already, or by now, depending on context.

In this sentence, already is the best fit:

• paries atrii iam sordidus est = the wall of the atrium is already dirty

It suggests a change or a contrast: the bedroom wall is white, but the atrium wall has already become dirty.

Latin word order is much more flexible than English word order. Iam is placed there naturally to modify the idea is already dirty.

Latin often places adverbs near the word or phrase they affect, but not always in exactly the same place English would. Here iam sordidus est neatly groups the idea is already dirty.

You could think of the sentence as emphasizing the contrast:

• bedroom wall: white
• atrium wall: already dirty

Because there are two complete clauses joined by sed:

• Paries cubiculi albus est
• sed paries atrii iam sordidus est

Each clause has its own subject and predicate, so each clause naturally has its own est.

Latin can sometimes omit a repeated verb if it is obvious, but repeating est is normal and clear.

Sed means but.

It connects the two clauses and shows contrast:

• the bedroom wall is white
• but the atrium wall is already dirty

It is a very common coordinating conjunction in Latin.

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

So:

• paries can mean a wall or the wall
• cubiculum can mean a bedroom or the bedroom

The context tells you which is meant. In this sentence, English naturally uses the.

Yes, often they could.

For example, Latin could rearrange parts of the sentence without changing the basic meaning, because the endings show the grammatical relationships. Word order often affects emphasis more than basic meaning.

This version:

• Paries cubiculi albus est, sed paries atrii iam sordidus est

is straightforward and easy to follow. It presents each clause in a clear pattern:

• subject
• genitive phrase
• adjective
• verb

That makes it especially suitable for learners.

Yes. They are both genitive singular forms of second-declension neuter nouns.

• cubiculum, cubiculi = bedroom
• atrium, atrii = atrium

In the genitive singular, second-declension nouns normally end in -i:

• servus → servi
• templum → templi
• cubiculum → cubiculi
• atrium → atrii

So both words are formed in the regular way.

Here it means dirty, grimy, or soiled.

It can describe literal dirt, which is clearly the meaning here. In other contexts, it can sometimes have a more figurative sense, such as mean, base, or squalid, but here the plain physical meaning is the one to learn first.

So the contrast is simple:

• albus = white
• sordidus = dirty

Because Latin does not require adjectives to come before the noun. Adjectives can come before or after, and placement often depends on style, rhythm, or emphasis.

Here:

• paries cubiculi albus est

puts the adjective near est, giving a simple predicate structure: the wall of the bedroom is white.

This is very common in Latin when an adjective is used with sum to describe the subject.

Yes. In this sentence albus is a predicate adjective, not just an adjective sitting inside a noun phrase.

So:

• paries albus = a white wall
• paries albus est = the wall is white

The same is true of sordidus est:

• paries sordidus est = the wall is dirty

That is why both adjectives are in the nominative: they describe the subject through the verb est.