Cum ex nundinis redierint, omnes fessi sed contenti erunt, quia vehiculum plenum erit et domus panem, pira, ac mustum habebit.

Here cum means when, not with.

Latin cum can introduce different kinds of clauses, but in this sentence it introduces a time clause:

Cum ex nundinis redierint = When they have returned from the market

So this is not the preposition cum meaning with. It is the conjunction cum meaning when.

Redierint is a future perfect form here: they will have returned.

Latin often uses the future perfect in a subordinate clause when that action will happen before another future action in the main clause.

So the sequence is:

• first: they return from the market
• then: they will be tired but happy, the cart will be full, and the house will have bread, pears, and must

That is why Latin says:

• Cum ... redierint = when they have returned
• ... erunt / erit / habebit = they will be / it will be / it will have

In natural English, we often just say when they return, but Latin marks the earlier future action more clearly.

Ex means out of or from, and it takes the ablative case.

So:

• ex nundinis = from the market / from market-day
• nundinis is ablative plural

This is a very normal Latin way to express movement away from a place or event.

Yes, but nundinae is one of those Latin nouns that is normally plural in form.

Historically, nundinae referred to the market day or market days, and Latin often treats it as a plural word even when English uses a singular translation like the market.

So:

• nundinae = market day / market
• ex nundinis = from the market

This is similar to how some English nouns are plural in form but may feel singular in meaning in certain contexts.

The subject is understood from the context and is the same group referred to by omnes later in the sentence.

So the sense is:

• when they have returned from the market
• all of them will be tired but happy

Latin often leaves pronouns unstated when the verb ending already tells you the person and number. The ending -erint shows third person plural, so they is understood.

They agree with omnes, which here means all (the people).

Because omnes refers to a plural group, the adjectives must also be plural:

• fessi = tired
• contenti = content / satisfied

The masculine plural form is the normal form for:

• a group of men
• a mixed group
• a group whose gender is not specified

If the group were definitely all female, Latin would usually use:

• fessae
• contentae

Because Latin often puts the verb later in the clause, especially when several words belong with it.

Here:

• omnes fessi sed contenti erunt

literally feels like:

• all tired but content will be

The verb erunt covers both adjectives:

• they will be tired
• they will be content

This is perfectly normal Latin word order. English usually places will be earlier, but Latin has much more freedom because the endings show how the words fit together.

Because plenum has to agree with vehiculum.

• vehiculum is neuter singular nominative
• so the adjective must also be neuter singular nominative
• therefore: plenum

So:

• vehiculum plenum erit = the vehicle/cart will be full

If the noun were masculine, you would expect plenus; if feminine, plena.

Latin can simply say plenum erit = it will be full, just as English can.

The context already tells you what it is full of: the things brought back from the market. So no extra phrase is necessary.

If Latin wanted to specify it, it could add something like fructuum or another expression depending on exactly what was meant. But here the writer leaves it understood from the context.

Domus is the subject of habebit:

• domus ... habebit = the house/home will have ...

A learner often notices that domus looks unusual. That is because it is an irregular noun, mostly of the fourth declension, though it has some mixed forms.

In this sentence, domus is nominative singular, serving as the subject.

Also, Latin can say the house will have bread, pears, and must, where English might sometimes prefer something like there will be bread, pears, and must in the house. Latin is comfortable using habere this way.

They are all direct objects of habebit, so they are in the accusative case.

• panem = accusative singular of panis
• pira = accusative plural of pirum
• mustum = accusative singular of mustum

They have different endings because they belong to different nouns and declension patterns.

A useful detail: pira is neuter plural, and neuter plural nominative and accusative forms are often the same. So pira can look less obviously accusative to an English-speaking learner, but here it is indeed an object.

Ac means and.

So:

• panem, pira, ac mustum = bread, pears, and must

Latin has more than one common word for and, including et and ac/atque. In many contexts they are very close in meaning.

A simple practical point:

• ac is a shorter form of atque
• it is very common before a consonant

So here ac mustum is just a normal stylistic choice.

Because the whole sentence is talking about a situation in the future.

Latin is showing a chain of future events:

1. they will have returned from the market
2. they will be tired but happy
3. the vehicle will be full
4. the house will have bread, pears, and must

The important distinction is this:

• redierint = future perfect, showing the return happens before the other future results
• erunt / erit / habebit = simple future, showing the resulting state

So the tense pattern is very deliberate.

Because Latin relies much more on word endings than on fixed word order.

English depends heavily on order:

• the house has bread is different from bread has the house

Latin, however, marks grammatical roles through case endings and verb endings, so it can move words around more freely.

This sentence is arranged in a very natural Latin way:

• the cum clause comes first to set the time
• omnes fessi sed contenti puts the people and their condition together
• quia introduces the reason
• then the two future results are listed:
  • vehiculum plenum erit
  • domus panem, pira, ac mustum habebit

So the order may feel unusual to an English speaker, but it is clear and idiomatic in Latin.