Coquus dicit cepam et allium in olla bene olere.

Because Latin normally uses indirect statement after verbs like dicit (he says).

In English, we say:

• The cook says that the onion and garlic smell good in the pot.

In Latin, instead of using a separate word for that, Latin usually uses:

• an accusative noun
  • an infinitive

So here:

• dicit = says
• cepam et allium ... olere = the onion and garlic to smell ...

That whole infinitive phrase is what the cook says.

This construction is often called the accusative-and-infinitive construction, or indirect statement.

Because in a Latin indirect statement, the subject of the infinitive goes into the accusative.

So although the onion and garlic are the things doing the smelling, Latin does not put them in the nominative here. Instead it uses the accusative because they are the subject of olere inside indirect statement.

• cepa = nominative, onion
• cepam = accusative

For allium, the form allium can be both nominative and accusative singular, because it is a neuter second-declension noun. So even though the form looks unchanged in English-style terms, it is functioning here as an accusative.

This is a very common question. With many neuter nouns in Latin, the nominative and accusative singular are identical.

So:

• allium = nominative singular garlic
• allium = accusative singular garlic

You tell which one it is from the grammar of the sentence, not from the form alone.

Here, since allium is part of the indirect statement after dicit, it is understood as accusative, parallel to cepam.

Olere is the present active infinitive of oleo, meaning to smell or to give off a smell.

It is used because indirect statement after dicit requires an infinitive. So instead of a finite verb like olet (smells), Latin uses:

• cepam et allium ... olere = the onion and garlic to smell ...

The present infinitive usually shows action happening at the same time as the main verb:

• Coquus dicit ... olere = The cook says that they smell... / are smelling...

Here it means to smell in the sense to give off a smell.

So:

• cepam et allium bene olere = the onion and garlic smell good

It does not mean to smell something with the nose here.

English uses smell for both ideas:

• The onion smells strong = gives off a smell
• I smell the onion = perceive the smell

Latin can distinguish these more clearly depending on the verb and construction. In this sentence, olere means to have a smell / give off an odor.

Because bene is an adverb, and it modifies the verb olere.

• bene = well
• olere bene = to smell well, which in natural English becomes to smell good

Latin uses an adverb because it is modifying the action/state expressed by the verb, not describing a noun directly.

Compare:

• bonus = good (adjective, used with nouns)
• bene = well (adverb, used with verbs)

So bene is exactly what Latin expects here.

Olla is in the ablative singular.

That is because in takes:

• ablative for location: in the pot
• accusative for motion into: into the pot

Here the meaning is location, not movement:

• in olla = in the pot

So Latin uses the ablative.

It goes with olere and tells you where the onion and garlic are smelling good.

So the sense is:

• The cook says [that the onion and garlic smell good] [in the pot].

It describes the setting or location of the smelling.

Because Latin word order is flexible, in olla appears before bene olere, but it still belongs with the infinitive phrase.

Yes, but not unusual for Latin. Latin word order is much freer than English word order.

The sentence is:

• Coquus dicit cepam et allium in olla bene olere.

A more English-like arrangement would be something like:

• Coquus dicit cepam et allium bene olere in olla.

But Latin often places words for emphasis, rhythm, or style rather than keeping a fixed order.

What matters most is the grammar:

• Coquus = subject of dicit
• cepam et allium = accusative subject of olere
• in olla = location
• bene = adverb modifying olere
• olere = infinitive of the indirect statement

Because Latin usually does not use a separate word meaning that in this kind of sentence.

English says:

• The cook says that the onion and garlic smell good.

Latin says:

• The cook says the onion and garlic to smell good.

That is just how Latin normally forms indirect statement. So the absence of that is not strange in Latin; it is the standard pattern.

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

So:

• coquus can mean the cook or a cook
• cepam can mean the onion or an onion
• in olla can mean in the pot or in a pot

You understand which is meant from context.

Coquus is the subject of the main verb dicit.

Inside the indirect statement, cepam et allium are the logical subject of olere, but grammatically they are in the accusative because of the indirect statement construction.

So there are really two layers:

1. Main clause:

   • Coquus dicit = The cook says

2. Indirect statement:

   • cepam et allium in olla bene olere = that the onion and garlic smell good in the pot

This is a very important Latin pattern to get used to.

Because olere is an infinitive, and infinitives do not change for singular or plural.

In English too, to smell stays the same:

• the onion to smell
• the onion and garlic to smell

Latin works the same way with the infinitive. Number is shown by the accusative subject phrase, not by changing olere.

Not in this sentence as written.

• olent would be a finite verb meaning they smell
• olere is the infinitive to smell

After dicit, Latin normally uses the infinitive for indirect statement:

• dicit ... olere = says that ... smell

If you used olent, you would be making a different kind of sentence, not the standard indirect statement construction shown here.

Because plain et is enough to join the two nouns:

• cepam et allium = the onion and the garlic

Latin certainly can say both ... and in other ways, but simple et is the normal and natural conjunction here.

It just links the two accusative nouns that act together as the subject of olere.