Colonus dicit novum axem huic vehiculo cras ponendum esse.

It has two parts:

• Colonus dicit = The farmer says
• novum axem huic vehiculo cras ponendum esse = the content of what he says

That second part is an indirect statement. In Latin, after verbs of saying, thinking, knowing, and so on, Latin often uses an accusative + infinitive construction instead of a clause with that.

So, instead of saying The farmer says that..., Latin says, more literally, The farmer says a new axle ... to have-to-be-put...

Because in an indirect statement, the subject of the infinitive is put in the accusative.

Here, axem is the thing that is understood as the subject of ponendum esse:

• axem ponendum esse = that the axle must be placed / that a new axle has to be put on

Even though axem would be the logical subject in English (a new axle must be put on...), Latin puts it in the accusative because it is the subject of an infinitive phrase.

ponendum esse is a gerundive + esse construction, often called the passive periphrastic.

It expresses necessity or obligation:

• poni = to be placed
• ponendum esse = to have to be placed, must be placed

So this does not just mean to be placed. It specifically adds the idea of must or needs to.

Because ponendum agrees with axem.

Here are the relevant forms:

• axem = accusative singular masculine
• novum = accusative singular masculine
• ponendum = accusative singular masculine

Although -um may look neuter to beginners, it is also the regular accusative singular masculine ending for many second-declension adjectives and participial adjectives.

So all three words match:

• novum axem ponendum
• a new axle [that] must be put...

huic vehiculo is dative singular: to/for this vehicle.

With a verb like pono, English often uses a preposition such as on, in, or for, but Latin can sometimes use the dative to show the thing affected or the thing for which something is intended.

So huic vehiculo means something like:

• for this vehicle
• on this vehicle
• to this vehicle

The most natural English wording depends on context, but grammatically it is a dative.

huic is the dative singular of hic, haec, hoc, meaning this.

It agrees with vehiculo:

• huic vehiculo = to/for this vehicle

Because vehiculo is neuter singular dative, huic is also dative singular.

cras means tomorrow, and it modifies the idea of ponendum esse.

So the sense is:

• that a new axle must be put on this vehicle tomorrow

It does not go especially with dicit here. In other words, the sentence means that the required putting-on is tomorrow, not primarily that the farmer is speaking tomorrow.

Latin word order is flexible, so cras can stand in different places without changing that basic sense.

Because Latin usually does not use a that-clause after verbs like say, think, or know the way English does.

English:

• The farmer says that a new axle must be put on this vehicle tomorrow.

Latin:

• Colonus dicit novum axem huic vehiculo cras ponendum esse.

So Latin replaces the English that-clause with an accusative-and-infinitive construction.

No, not explicitly.

The passive periphrastic tells you that something must be done, but it does not always state by whom. If Latin wants to say who has the obligation, it often uses a dative of agent.

For example, a sentence could say that the axle must be put on by the farmer, using a dative with the passive periphrastic. But in your sentence, no such dative of agent appears.

So the sentence gives the obligation, but not the person responsible.

Because Latin word order is much freer than English word order.

English depends heavily on position:

• subject + verb + object

Latin depends more on endings. Because the endings already show each word’s role, Latin can move words around for emphasis, rhythm, or style.

In this sentence:

• Colonus is clearly nominative, so it is the subject of dicit
• axem is accusative, so it belongs to the indirect statement
• huic vehiculo is dative
• ponendum esse comes at the end, where Latin often places the verbal idea

So even though the order feels unusual in English, the grammar is clear in Latin.

Yes, but it would mean something different.

• poni = to be placed
• ponendum esse = must be placed

So if the sentence had novum axem huic vehiculo cras poni, it would only express the action as something happening or being said to happen. It would not express obligation.

The actual sentence uses ponendum esse because the meaning includes necessity: the new axle has to be put on the vehicle.