Insula altum aedificium est.

That is a very common question. Insula originally does mean island, but in Roman city life it also came to mean a block of buildings or, more commonly in teaching contexts, an apartment building / tenement building.

So in this sentence, insula is not island. The rest of the sentence makes that clear, because it is being identified as altum aedificium, a tall building.

Latin often has words with more than one meaning, and context tells you which meaning is intended.

Because altum is describing aedificium, not insula.

• insula is feminine singular
• aedificium is neuter singular
• altum is also neuter singular

In Latin, adjectives agree with the noun they modify in gender, number, and case. Here:

• altum aedificium = a tall building

So the adjective matches aedificium, which is neuter, and that is why it is altum, not alta.

If you said insula alta est, then alta would be agreeing with insula, and the meaning would be the apartment building is tall.

Both are in the nominative singular.

• insula is the subject
• aedificium is the predicate nominative after est

This is normal in Latin when one noun is being equated with another:

• X est Y = X is Y

So here:

• Insula = the thing being talked about
• aedificium = what it is being identified as

Even though the two nouns have different genders, they can both be nominative because they are linked by est.

Aedificium is a neuter noun meaning building.

It belongs to the second declension, which is why its nominative singular ends in -um. That -um ending is very common for second-declension neuter nouns.

So:

• aedificium = building
• altum aedificium = tall building

A learner may notice that -um also appears on the adjective altum. That is not a coincidence: both are neuter singular nominative.

Because Latin does not have articles like English a, an, and the.

So a Latin sentence often leaves that idea unstated, and English has to supply it when translating.

For example:

• aedificium can mean a building or the building, depending on context
• insula altum aedificium est can be translated naturally as The insula is a tall building or An insula is a tall building, depending on the situation

English requires an article, but Latin does not.

It certainly can, but that would be a slightly different structure.

• insula alta est = the insula is tall
• insula altum aedificium est = the insula is a tall building

The first sentence uses an adjective directly with the subject:

• alta describes insula

The second sentence identifies the subject as belonging to a category:

• aedificium = building
• altum describes that building

In English, these can sound very similar, but Latin is showing two different grammatical patterns.

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

Putting the verb at the end is very common, especially in simple textbook-style sentences and in much classical prose. So:

• Insula altum aedificium est

is a perfectly normal order.

English usually requires:

• The insula is a tall building

But Latin often saves the verb for last.

Yes. Latin word order is flexible, because the endings show the grammatical relationships.

For example, these are possible:

• Insula altum aedificium est
• Insula aedificium altum est
• Altum aedificium insula est

They all express roughly the same basic idea, though the emphasis changes.

The given order is straightforward and natural for learning:

• subject first: insula
• description next: altum aedificium
• verb last: est

So the sentence is not locked into one order the way an English sentence usually is.

Latin adjectives can come before or after the noun they modify.

So both of these are possible:

• altum aedificium
• aedificium altum

Both mean tall building.

The position can sometimes affect emphasis or style, but at an early stage the important point is this: Latin adjective placement is much freer than English adjective placement.

What matters most is the agreement:

• altum matches aedificium
• both are nominative singular neuter