Canis ad ianuam sedet.

Canis is nominative singular, the form used for the subject of the sentence. Since the dog is the one doing the action of sitting, Latin puts canis in the nominative.

Its dictionary form is also canis, so in this sentence the basic form happens to be the correct subject form.

Because ad normally takes the accusative case, and ianuam is the accusative singular of ianua (door).

So:

• ianua = nominative singular, door
• ianuam = accusative singular, used after ad

This is a very common pattern in Latin:

• ad villam = to/at the house
• ad urbem = to/at the city
• ad ianuam = to/at the door

Ad usually means to, toward, or at/by, depending on context.

In Canis ad ianuam sedet, it is often best understood as at the door or by the door. Even though ad often suggests motion toward something, Latin also uses it in expressions of position like this.

So ad ianuam is a natural Latin way to say at the door.

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

So canis can mean:

• a dog
• the dog

And ianuam can mean:

• a door
• the door

The exact meaning depends on context. English has to choose, but Latin usually does not mark that distinction directly.

The ending -t shows that the verb is third person singular: he/she/it sits.

So:

• sedeo = I sit
• sedes = you sit
• sedet = he/she/it sits

Since canis is one dog, the singular verb sedet is used.

The dictionary form is sedeo, meaning I sit or I am sitting.

Latin verbs are usually listed in the first person singular present form in dictionaries. From sedeo, you can get forms like:

• sedeo = I sit
• sedes = you sit
• sedet = he/she/it sits
• sedemus = we sit

So sedet is a conjugated form of sedeo.

Yes. Latin word order is much more flexible than English word order because the endings show each word’s role.

So all of these could mean the same thing:

• Canis ad ianuam sedet.
• Ad ianuam canis sedet.
• Sedet canis ad ianuam.

The most neutral or straightforward order here is fine as written, but Latin can move words around for emphasis or style.

Canis can be masculine or feminine, depending on the sex of the dog.

So this sentence could mean:

• the male dog sits at the door
• the female dog sits at the door

Latin does not always make that explicit unless the context or an adjective makes it clear.

In this sentence, sedet tells you that the subject must be singular, because sedet means he/she/it sits.

If the subject were plural, the verb would also be plural:

• Canis ... sedet = The dog sits
• Canes ... sedent = The dogs sit

So the verb ending helps confirm that canis here is singular.

It would be:

Canes ad ianuam sedent.

Changes:

• canis → canes = dogs
• sedet → sedent = sit

Ad ianuam stays the same, because there is still just one door in the phrase.

In restored Classical pronunciation, ianuam is pronounced roughly like yah-noo-am.

A few helpful points:

• initial i before a vowel often sounds like English y
• u sounds like oo
• each vowel is pronounced

So:

• ianua ≈ YAH-noo-a
• ianuam ≈ YAH-noo-am

They are:

• canis, canis = dog
• ad = to, toward, at
• ianua, ianuae = door
• sedeo, sedere = sit

If you want the sentence broken down morphologically:

• canis = nominative singular
• ad = preposition taking the accusative
• ianuam = accusative singular
• sedet = 3rd person singular present active

By itself, ad ianuam can often mean to the door. But in this sentence the verb is sedet (sits), which describes being in a position rather than moving.

Because of that, English usually translates the whole phrase more naturally as at the door or by the door, not to the door.

So the verb helps determine the best translation of the prepositional phrase.