Mercator ex Sicilia ad Brundisium navigat.

Mercator is nominative singular. It is the subject of the sentence, so nominative is the expected case.

A learner may also want to know its dictionary form:

• mercātor, mercātōris = merchant

So here mercator means the merchant / a merchant as the subject doing the action.

Because ex is a preposition that takes the ablative case and means out of, from.

So:

• ex = from, out of
• Siciliā = ablative form of Sicilia

In a fully marked text with macrons, you would usually see ex Siciliā.

This is one of the most important beginner patterns in Latin:

• ex + ablative = out of / from
• ab + ablative = from / away from
• ad + accusative = to / toward

Because ad takes the accusative case and means to or toward.

So here:

• ad = to, toward
• Brundisium = accusative singular

This gives the destination of the motion.

A very common beginner pattern is:

• ex
  • ablative = where someone comes from
• ad
  • accusative = where someone goes to

Because Brundisium is a neuter second-declension noun, and in that declension the nominative singular and accusative singular have the same form.

So:

• nominative singular: Brundisium
• accusative singular: Brundisium

Even though the form looks unchanged, its job in the sentence is different. After ad, it is understood as accusative.

Yes, in classical Latin, movement toward a town or city is often expressed with the accusative without a preposition:

• Romam it = he goes to Rome
• Brundisium venit = he comes to Brundisium

So an English speaker may notice that ad Brundisium is not the only possible way.

That said, ad Brundisium is perfectly understandable and is often used in beginner Latin or when the writer wants to stress movement toward the place.

Navigat is a verb in the:

• present tense
• active voice
• indicative mood
• third person singular

It comes from nāvigāre, meaning to sail, to travel by ship, or sometimes more generally to voyage.

The ending -t tells you the subject is:

• he
• she
• it

So navigat means he/she sails, he/she is sailing, or he/she travels by ship, depending on context.

Because Latin usually does not need an explicit subject pronoun when the verb ending already makes the subject clear.

Here, navigat ends in -t, which already tells you the subject is third person singular.

So Latin can simply say:

• Mercator ... navigat

rather than adding a separate word for he.

If Latin did include a pronoun such as is, that would usually add emphasis or contrast.

It can mean either, depending on context.

Latin present tense often covers both:

• simple present: sails
• progressive present: is sailing

So this sentence can naturally be understood as either:

• The merchant sails from Sicily to Brundisium
• The merchant is sailing from Sicily to Brundisium

English forces you to choose more often than Latin does.

Because classical Latin has no articles like English the and a/an.

So mercator can mean:

• the merchant
• a merchant

The context tells you which is best in translation.

This is very normal in Latin. A noun by itself does not automatically tell you whether it is definite or indefinite.

The word order is natural, but Latin word order is more flexible than English word order.

Here the sentence is:

• Mercator = subject
• ex Sicilia = place of origin
• ad Brundisium = destination
• navigat = verb

Latin often puts the verb near the end, but other orders are possible because the cases and prepositions already show the relationships.

For example, Latin could rearrange this sentence for emphasis without changing the basic meaning.

Because Latin treats different kinds of place names differently.

A useful beginner rule is:

• cities and small islands often use special case constructions without prepositions
• larger regions, provinces, and large islands often use prepositions

So:

• Sicily is a large island / region, so ex Siciliā is normal.
• Brundisium is a city, and classical Latin often allows motion toward it without ad.

This is one of those place-name rules that English speakers usually need time to get used to.

Very literal:

• Mercator = the merchant
• ex Sicilia = from Sicily
• ad Brundisium = to Brundisium
• navigat = sails

So the sentence builds a clear path:

subject → point of departure → destination → action

Latin often expresses movement very neatly this way.

A reasonable classical-style pronunciation would be:

mer-CAH-tor ex si-KI-li-ah ad broon-DI-si-um NAH-wi-gat

A few helpful points:

• c is always hard, like k
• v is pronounced like English w in classical pronunciation
• g is always hard
• the stress usually falls on:
  • mercātor → -cā-
  • Sicilia → -ci-
  • Brundisium → -di-
  • nāvigat → first syllable

If you are using an ecclesiastical pronunciation, some sounds would be different, especially c before i.

Because teaching materials often add macrons to show long vowels.

With macrons, you might see:

Mercātor ex Siciliā ad Brundisium nāvigat.

Macrons help with:

• pronunciation
• stress
• recognizing forms

But many Latin texts, especially older ones or simpler classroom materials, leave them out. So it is normal to see both versions.