Quaedam in foro tacent, aliae clamant.

They are forms of words that are normally adjectives or pronouns, but here they are being used substantively—that is, they stand by themselves as nouns.

• quaedam is from quidam, quaedam, quiddam, meaning a certain or some
• aliae is from alius, alia, aliud, meaning other

So here they mean something like:

• quaedam = some ones / certain ones
• aliae = other ones / others

Latin does this very often: it leaves the noun understood if the context makes it clear enough.

Because they agree with an understood feminine plural noun.

In Latin, words like quaedam and aliae must show gender, number, and case. English some and others do not show gender, but Latin does.

So this sentence tells us that the hidden subject is feminine plural. Depending on context, that might be something like:

• mulieres = women
• or any other feminine plural noun already mentioned

If the sentence is shown by itself, all we can say for sure is that the subjects are feminine plural.

Mainly from the context of the sentence:

• tacent is third person plural: they are silent
• aliae is clearly plural
• the structure quaedam ... aliae ... strongly means some ... others ...

So even though quaedam can sometimes be ambiguous in form, here it is understood as nominative feminine plural.

Because Latin often omits a noun when it is easy to understand from context.

So instead of saying something like:

• Quaedam mulieres in foro tacent, aliae mulieres clamant

Latin can simply say:

• Quaedam in foro tacent, aliae clamant

This is completely normal. English sometimes does the same thing with some and others, but Latin does it even more freely.

foro is ablative singular of forum.

It is ablative because it follows in in the sense of location:

• in foro = in the forum / at the forum

A very useful rule is:

• in + ablative = location, in/on/at
• in + accusative = motion into, into

So:

• in foro = in the forum
• in forum = into the forum

Either can be a good English translation depending on context.

The Latin phrase in foro literally means in the forum, but English may prefer:

• in the forum
• at the forum
• sometimes even in the marketplace or in the public square

That is because the Roman forum was not just one abstract idea; it was a public civic space used for business, politics, and social activity.

Both are:

• present tense
• active voice
• indicative mood
• third person plural

So:

• tacent = they are silent / they keep quiet
• clamant = they shout / they are shouting

The verbs match the plural subjects quaedam and aliae.

Because tacent does not mean are silent by using a linking verb plus adjective. It is a single verb meaning are silent, keep quiet, or remain silent.

So Latin is not saying:

• they are silent with a form of to be
  • adjective

Instead it uses the verb:

• tacere = to be silent / keep silent

Likewise:

• clamare = to shout

Because Latin often does not need an extra connecting word when the contrast is already obvious.

The pair quaedam ... aliae ... already creates the contrast:

• some ... others ...

That makes the relationship clear without needing et (and) or sed (but).

So the sentence has a neat balanced structure:

• Quaedam ... tacent, aliae clamant.
• Some are silent ..., others shout.

Yes, but not in the same rigid way as in English.

A straightforward English-speaking learner might expect a fixed order, but Latin is more flexible. Here the order is quite natural:

• Quaedam — the first group
• in foro — where they are
• tacent — what they do
• aliae — the contrasting group
• clamant — what they do

Putting quaedam first and aliae later helps emphasize the contrast between the two groups. The sentence is very balanced and elegant.

Yes. The word quidam / quaedam / quiddam often means a certain or certain.

So in another context, quaedam could mean:

• certain women
• certain people
• certain things

But in this sentence, because it is paired with aliae, the most natural sense is:

• some ... others ...

That contrast is stronger than the vaguer English idea of certain.

Usually here it just means others.

Latin alius means other, and in a contrast like quaedam ... aliae ..., it means:

• some ... others ...

It does not necessarily mean all the rest in a strict mathematical sense. It simply divides the group into two contrasting parts.

So the sentence presents two sets:

• some are silent
• others shout