Canalis longus est.

Canalis is a third-declension noun. In this sentence it is nominative singular, because it is the subject of the verb est.

Its dictionary form is canalis, canalis (masculine), and the nominative singular happens to end in -is.

It is nominative singular.

You can tell because canalis is the thing being described: the canal is long. In Latin, the subject of the sentence is normally in the nominative case.

Because adjectives in Latin do not have to look exactly the same as the nouns they describe. They have to match in:

• gender
• number
• case

Here, canalis is masculine nominative singular, so the adjective must also be masculine nominative singular. For the adjective longus, longa, longum, the masculine nominative singular form is longus.

So:

• canalis = masculine nominative singular
• longus = masculine nominative singular

They agree, even though their endings are different.

It is a predicate adjective.

That means it is linked to the subject by a form of to be:

• Canalis longus est = The canal is long

This is different from an adjective used directly inside a noun phrase:

• canalis longus = the long canal / a long canal

So in your sentence, longus is not just attached to the noun by itself; it is part of the statement made with est.

Est means is.

It is the third-person singular present active indicative of esse, the verb to be.

So:

• sum = I am
• es = you are
• est = he/she/it is

Since canalis is singular, est is singular too.

Because Latin usually does not use articles like English does.

So canalis can mean:

• the canal
• a canal
• sometimes just canal, depending on context

English has to choose the or a, but Latin often leaves that unstated unless the context makes it clear.

Latin word order is more flexible than English word order.

Putting est at the end is very normal in Latin. The sentence could also appear as:

• Canalis est longus
• Longus est canalis
• Longus canalis est

These can all mean basically the same thing, though the emphasis may shift slightly.

So Canalis longus est is a perfectly normal Latin order.

Yes.

Both Canalis longus est and Canalis est longus mean The canal is long.

Latin often allows different word orders because the endings show the grammar. A writer may choose one order or another for style, rhythm, or emphasis.

Because canalis is the noun, and longus is an adjective agreeing with it.

In a sentence with esse (to be), a noun can be described by an adjective:

• subject: canalis
• predicate adjective: longus
• verb: est

So the structure is:

The canal + is + long

not

The long one + is + canal

Yes, canalis is usually masculine.

That is why the adjective is longus and not:

• longa (feminine)
• longum (neuter)

Gender in Latin is grammatical, so you learn it as part of the noun.

A common classroom pronunciation would be roughly:

kah-NAH-lis LON-goos est

If you want a more classical-style pronunciation:

• c is always hard, like k
• a is like a in father
• g is always hard
• u is like oo in food

So longus sounds like LON-goos, not like English long-gus.

You would make all the relevant words plural:

Canales longi sunt.

Here:

• canales = canals
• longi = long (masculine nominative plural)
• sunt = are

This shows the same agreement pattern as the singular sentence.