Nobilitas in contione tacet, vulgus autem clamat.

Both words are collective nouns.

• nobilitas means the nobility or the noble class
• vulgus means the common crowd, the masses, or the common people

Even though they refer to many people, each word is grammatically singular in Latin here, so each takes a singular verb:

• nobilitas ... tacet = the nobility is silent
• vulgus ... clamat = the crowd shouts

This is similar to English collective nouns like the audience, the crowd, or the nobility.

contione is ablative singular of contio.

The preposition in can take two different cases:

• accusative for motion into something
• ablative for location in or at something

Here there is no motion; the sense is in the assembly or at the public meeting, so Latin uses in + ablative:

• in contione = in/at the assembly

contio means a public meeting, assembly, or political gathering, especially one where people speak before a crowd.

So in contione does not just mean being physically inside some building. It means being at a public assembly or in the setting of public speaking and politics.

autem means however, but, or on the other hand.

It introduces a contrast:

• Nobilitas in contione tacet
• vulgus autem clamat

So the sense is: The nobility is silent in the assembly, but the crowd shouts.

A useful thing to notice is that autem is very often placed second in its clause in Latin. That is exactly what happens here:

• vulgus autem clamat

Latin word order is much freer than English word order because Latin uses case endings and verb forms to show grammatical relationships.

English depends heavily on word order:

• The crowd shouts

Latin can move words around more easily:

• Vulgus clamat
• Clamat vulgus
• Vulgus autem clamat

In this sentence, the order helps the contrast stand out:

• Nobilitas ... tacet
• vulgus autem ... clamat

The structure balances the two groups against each other.

Classical Latin has no definite article and no indefinite article.

So:

• nobilitas can mean the nobility
• vulgus can mean the crowd or the common people
• contio can mean an assembly or the assembly

The exact English article depends on context. In this sentence, English usually adds the because the meaning is more natural that way.

Both are present tense, third person singular, active:

• tacet = is silent, keeps silent, or is keeping silent
• clamat = shouts, is shouting

In Latin, the present tense can describe:

• a general truth
• a habitual action
• something happening right now
• a vivid scene in narrative

Here it could be understood as a general observation or as a vivid present scene.

The dictionary forms are:

• nobilitas, nobilitatis (f.) = nobility
• contio, contionis (f.) = assembly, public meeting
• taceo, tacere, tacui = to be silent
• vulgus, vulgi (n.) = the common people, crowd
• autem = however, but
• clamo, clamare, clamavi, clamatus = to shout

Looking up the dictionary form is important because the endings in the sentence may be different from the form listed in a dictionary.

Yes, it matters for agreement.

• nobilitas is feminine
• vulgus is neuter

In this sentence, there are no adjectives agreeing with them, so the gender is not very visible. But if adjectives were added, they would have to match the noun in gender, number, and case.

Even though vulgus refers to people, it is grammatically neuter singular.

Either can work, depending on context.

• is silent is a straightforward translation
• keeps silent brings out the idea of remaining silent or choosing not to speak

Latin tacere often means not just the absence of sound, but specifically not speaking. In a political assembly, that nuance can matter: the nobility may be present, but not speaking, while the crowd is vocal.

clamat simply means shouts or is shouting. The present tense does not by itself tell you whether it is a single cry or ongoing noisy behavior.

Because vulgus is a collective noun, the sense is usually that the crowd is shouting or raising a loud outcry, not that one single person gives one single shout.

Sometimes, depending on context, English may use in the assembly, at the assembly, or even before the assembly if the idea is public speaking in front of a gathered crowd.

Strictly speaking, in contione means in/at the assembly. But natural English may shift a little if that better matches the situation being described.

Yes. The sentence is neatly balanced and contrasts two groups:

• Nobilitas ... tacet
• vulgus autem ... clamat

This makes the statement feel sharp and epigrammatic. The silence of the elite is set directly against the noise of the crowd. Latin often likes this kind of compact contrast.