Nonnullae feminae ad forum festinant, sed nonnulli viri domi manent.

Because they agree with different nouns.

• nonnullae goes with feminae (women), which is feminine plural
• nonnulli goes with viri (men), which is masculine plural

In Latin, adjectives and adjective-like words must agree with the nouns they describe in gender, number, and case.

So:

• nonnullae feminae = some women
• nonnulli viri = some men

It usually means some or several.

Literally, it comes from non + nullus, so the idea is something like not none, but in normal English that is best translated as some or several.

So:

• nonnullae feminae = some women
• nonnulli viri = some men

It does not usually mean not a few in a dramatic English sense here; it is simply a common Latin way to say some.

Because they belong to different noun declensions.

• femina is a first-declension noun

  • singular: femina
  • plural: feminae

• vir is a second-declension noun

  • singular: vir
  • plural: viri

So both are plural, but Latin uses different plural endings depending on the noun’s declension.

They are both nominative plural, because they are the subjects of their verbs.

• Nonnullae feminae ... festinant = Some women ... hurry
• nonnulli viri ... manent = some men ... remain

The subject of a finite verb is normally in the nominative case in Latin.

Clues:

• feminae can be nominative plural
• viri is nominative plural
• the verbs festinant and manent are both third person plural, so plural subjects make sense

Because ad takes the accusative case.

The preposition ad usually means to, toward, or to the vicinity of, and the noun after it must be accusative.

• forum is the accusative singular of forum
• so ad forum = to the forum

This is a very common pattern in Latin:

• ad villam = to the house/farm
• ad urbem = to the city
• ad forum = to the forum

Because domi is a special locative form meaning at home.

Latin has a small set of words that can use the locative, a case used mainly for place where. Domus is one of them.

• domi = at home
• domum = homeward / to home
• domo = from home

So in this sentence:

• domi manent = they remain at home

If the sentence meant they go home, you would expect domum instead.

They are both present tense.

• festinant = they hurry / are hurrying
• manent = they remain / are remaining / stay

Latin present tense can often be translated in more than one natural English way, depending on context:

• simple present: they hurry
• progressive: they are hurrying

Because -nt is the usual ending for third person plural in the present tense.

Here both subjects are plural:

• nonnullae feminae = some women
• nonnulli viri = some men

So the verbs are plural too:

• festinant = they hurry
• manent = they remain

This subject-verb agreement is an important feature of Latin.

Sed means but.

It connects the two clauses:

• Nonnullae feminae ad forum festinant
• sed nonnulli viri domi manent

So the structure is:

Some women hurry to the forum, but some men remain at home.

It is a very common coordinating conjunction.

Classical Latin normally has no articles.

So a noun like forum can mean:

• the forum
• a forum

depending on context.

Likewise:

• feminae can mean women or the women
• viri can mean men or the men

English requires articles much more often, but Latin usually leaves that information to context.

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

This sentence uses a clear and straightforward arrangement:

• Nonnullae feminae = subject
• ad forum = direction
• festinant = verb
• sed = connector
• nonnulli viri = new subject
• domi = place
• manent = verb

Latin could rearrange some of these words without changing the basic meaning, though the emphasis might change. For example, placing domi earlier or later could shift attention slightly, but viri would still be the subject because of its form.

They describe opposite kinds of action.

• festinare means to hurry, to hasten
• manere means to remain, to stay

So the sentence contrasts movement and staying still:

• some women are hurrying to the forum
• some men are staying at home

That contrast is reinforced by sed = but

Because the number of the destination does not depend on the number of people going there.

The sentence says many women are going to one place: the forum.

So:

• feminae is plural because there are multiple women
• forum is singular because it is a single destination

English works the same way: Some women hurry to the forum, not to the forums, unless there are actually several forums.