Vulgus interdum falsae famae cito cedit.

Because vulgus is a collective noun. In Latin, it is grammatically singular, even though it refers to a group of people.

So:

• vulgus = the crowd, the masses, the common people
• it takes a singular verb
• that is why the sentence has cedit (it yields) rather than cedunt (they yield)

This is similar to how English can sometimes use a singular word for a group, like the public.

Vulgus is nominative singular, which makes it the subject of the sentence.

We know this because:

• cedit is a third-person singular verb
• the thing doing the action is therefore a singular subject
• vulgus fits that role perfectly

So the basic structure is:

• vulgus = subject
• cedit = verb

Cedit is:

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

It comes from cedere, which often means:

• to yield
• to give way
• to submit
• sometimes to fall prey to, depending on context

So cedit here means something like yields, gives way, or gives in.

Because cedere commonly takes the dative of the thing or person one yields to.

So Latin says, literally:

• the crowd yields to false rumor

not:

• the crowd yields false rumor

That is why we get:

• falsae famae = to false rumor / to a false report

This is a very common kind of question for English speakers, because English usually uses a preposition such as to, while Latin often expresses that idea just by using the dative case.

The form falsae famae could look ambiguous at first, but in this sentence it is best understood as dative singular:

• falsae = dative singular feminine of falsus, falsa, falsum
• famae = dative singular of fama

Why dative?

• because cedere regularly takes the dative
• the sense required is yielding to something

So falsae famae means to false rumor or to a false report.

Fama can mean several related things, including:

• report
• rumor
• talk
• reputation
• fame

In this sentence, because it is modified by falsae (false) and depends on cedit (yields to), the most natural meaning is:

• false rumor
• false report

So this is not fame in the modern English sense of celebrity. It is more like what people are saying, especially when that report is unreliable.

Both are adverbs.

• interdum = sometimes
• cito = quickly

They modify the verb cedit:

• interdum tells us how often
• cito tells us how quickly

So the sense is:

• the crowd sometimes yields quickly to false rumor

or more naturally:

• the crowd sometimes quickly gives way to false rumor

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

Here:

• vulgus = subject
• falsae famae = dative object with cedit
• interdum and cito = adverbs
• cedit = verb, placed at the end

Putting the verb at the end is very common in Latin prose. So even though the order may feel unusual to an English speaker, the sentence is perfectly normal Latin.

A more English-like order would be something like:

• Vulgus cito interdum falsae famae cedit
• or Vulgus falsae famae interdum cito cedit

But Latin does not need a fixed order the way English does.

Yes, it can. Vulgus often refers to:

• the common crowd
• the masses
• ordinary people

Depending on context, it may sound fairly neutral, but it can also carry a slightly dismissive tone, like:

• the mob
• the rabble
• the common herd

In this sentence, since the crowd is described as giving way to false rumor, vulgus may suggest the idea that the masses are easily misled.

Yes—probably the most useful grammar point is this:

cedere often takes the dative.

So from this sentence, a learner should remember:

• cedit = yields
• alicui rei cedere = to yield to something

That makes falsae famae much easier to understand.

A second useful point is that vulgus is a singular collective noun, so it takes a singular verb even though it refers to many people.