Semita angusta ad limitem agri ducit; alter limes ad veterem pontem descendit.

Because angusta is describing semita. In Latin, adjectives must agree with the nouns they describe in:

• gender
• number
• case

Semita is feminine, singular, nominative, so the adjective must also be feminine, singular, nominative: angusta.

So:

• semita = path
• angusta = narrow

Together, semita angusta means a/the narrow path.

Because the preposition ad takes the accusative case when it means to or toward.

The basic dictionary form is limes, but after ad it changes to the accusative singular limitem.

So:

• limes = nominative singular
• limitem = accusative singular

The same thing happens later in ad veterem pontem: pontem is also accusative because it follows ad.

Agri is the genitive singular of ager, meaning field.

The genitive often expresses the idea of of in English. So:

• limitem agri = the boundary/edge of the field

A learner should get used to this pattern:

• Latin often uses the genitive
• English often uses of

So agri tells you whose boundary it is: the field’s boundary.

Yes. They are two different forms of the same noun:

• limes = nominative singular
• limitem = accusative singular

This noun belongs to the third declension, so its forms are less predictable than first- or second-declension nouns.

In this sentence:

• limitem appears after ad, so it must be accusative
• limes is the subject of descendit, so it is nominative

Because Latin words often have a range of meanings, and limes is one of those words.

Depending on context, limes can mean things like:

• boundary
• edge
• path
• track

So:

• limitem agri naturally suggests the boundary/edge of the field
• alter limes naturally suggests another path/track

This is normal in Latin. Context tells you which English word fits best.

Alter usually means the other (of two) or the second.

In smooth English, it is often translated as another, especially when English sounds more natural that way.

So alter limes literally means something like:

• the other path
• the second path

It agrees with limes, so it is:

• masculine
• singular
• nominative

Because both words have changed form to fit their job in the sentence.

The dictionary forms are:

• vetus = old
• pons = bridge

But after ad, the noun must be accusative, so:

• pons becomes pontem

And the adjective must agree with it, so:

• vetus becomes veterem

So:

• vetus pons = an old bridge / the old bridge
• ad veterem pontem = to an old bridge / to the old bridge

In Latin, you do not identify the subject mainly by word order. You identify it by case.

Here the subjects are:

• semita in the first clause
• limes in the second clause

Both are nominative singular, and each goes with a singular verb:

• semita ... ducit
• alter limes ... descendit

The phrases with ad are not subjects; they are prepositional phrases showing direction:

• ad limitem agri
• ad veterem pontem

Because Latin word order is much more flexible than English word order.

Both of these are perfectly normal:

• semita angusta
• veterem pontem

The endings show which words belong together, so Latin does not depend as heavily on position as English does.

At a beginner level, the important thing is:

• angusta agrees with semita
• veterem agrees with pontem

So even though the order is different, the grammar is clear.

Because Latin has no articles.

That means Latin does not have separate words for:

• a
• an
• the

So semita angusta could mean:

• a narrow path
• the narrow path

And veterem pontem could mean:

• an old bridge
• the old bridge

You choose the best English wording from the context.

Yes. This is a normal way of speaking in Latin.

Latin often uses verbs like these with roads, paths, and tracks:

• ducit = leads
• descendit = goes down, descends

So the sentence is treating the route itself as doing the action, just as English can say:

• The road leads to the village
• The path goes down to the river

That is why semita ... ducit and limes ... descendit sound natural in Latin.