Mater audit frumentum quoque ex Africa ad urbem portari.

Mater is the subject of the main verb audit. It is in the nominative singular.

A learner might expect a mother-word to end in -a, but mater is not a first-declension noun. It is a third-declension noun: mater, matris.

Audit is the 3rd person singular present active indicative of audire.

So it means he/she hears.
In a sentence like this, it can often be understood a bit more broadly as hears that... or learns that..., depending on context.

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

Instead, after verbs like hear, say, think, know, and similar verbs, Latin commonly uses an accusative + infinitive construction:

• Mater audit
• frumentum ... portari

This literally works like: Mother hears grain to be carried..., but in normal English we translate it as Mother hears that grain is being carried...

Because it is the subject of the infinitive portari inside an indirect statement.

In English, we would say:

• Mother hears that grain is being carried...

In Latin, the subject of that reported idea is put in the accusative, so:

• frumentum = the thing that is being carried

Even though it is the logical subject of portari, it appears in the accusative because of this construction.

Because Latin uses the infinitive in indirect statements after verbs like audit.

So instead of saying something like:

• Mater audit quod frumentum portatur

Latin more classically prefers:

• Mater audit frumentum portari

Here portari is the verb of the reported statement.

Portari is the present passive infinitive of portare, meaning to be carried.

It is passive because frumentum is not doing the carrying; it is being carried.

So:

• portare = to carry
• portari = to be carried

In indirect statement, the tense of the infinitive shows time relative to the main verb, not absolute time.

Since portari is a present infinitive, it shows action happening at the same time as audit.

So the sense is:

• Mother hears that the grain is being carried

If the carrying had happened earlier, Latin would use a perfect infinitive instead.

Quoque means also or too.

It often comes after the word it especially relates to. So:

• frumentum quoque = grain too / also grain

That suggests that something else is being carried as well, and grain is being added to the list.

This is different from English, where also often comes before the word it modifies.

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

So:

• ex Africa = from Africa

Africa here is in the ablative singular.

Because ad means to or toward, and it shows motion in the direction of a place.

So:

• ad urbem = to the city

Also, ad takes the accusative case, which is why we get urbem rather than urbs.

Urbem is accusative singular of urbs, urbis.

It is accusative because it follows ad, and ad takes the accusative when it means to/toward.

So:

• urbs = nominative
• urbem = accusative

Because Latin has no articles.

So a noun like mater can mean:

• mother
• the mother
• a mother

And urbem can mean:

• city
• the city

You figure out which is best from the context and the intended meaning.

Latin word order is more flexible than English word order, because the endings show the grammatical relationships.

This sentence is arranged quite naturally:

• Mater = subject
• audit = main verb
• frumentum ... portari = indirect statement

But Latin could move pieces around for emphasis. For example, putting ex Africa earlier or later would not usually change the basic meaning.

What matters most is the grammar of the forms, not just the position.

Here frumentum means grain as a substance or supply, not a single grain.

Latin often uses the singular for this kind of mass noun. So even though English speakers might think of many separate grains, Latin frumentum commonly means grain collectively.

It can be either, depending on context.

• Literally: Mother hears...
• More broadly: Mother hears that... / learns that...

With an indirect statement like this, English often translates it in the broader information sense, even though the Latin verb is still audire.