In bibliotheca nemo omnino clamare audet; qui aliquid dicere vult, amico tantum susurrat.

Because in can take either the ablative or the accusative, depending on meaning:

• in + ablative = in / inside / at a place, with no motion
• in + accusative = into a place, showing motion toward it

Here in bibliotheca means in the library, so it describes location, not movement. That is why bibliotheca is in the ablative.

Nemo means no one / nobody and is grammatically singular in Latin. So the verb is singular too:

• nemo audet = no one dares

Even though in English nobody can sometimes feel like it refers to many people, Latin treats nemo as one grammatical subject.

Omnino is an adverb meaning altogether, entirely, absolutely, or in many contexts at all.

So nemo omnino clamare audet means something like:

• no one dares to shout at all
• absolutely no one dares to shout

It strengthens the negation and makes the statement more emphatic.

The verb audeo, audere means to dare, and it commonly takes a complementary infinitive. That is very similar to English:

• I dare speak
• he dares shout

So:

• clamare = to shout
• audet = he/she dares

Together, clamare audet means dares to shout.

This is a very common Latin pattern with verbs like:

• possum
  • infinitive = can
• volo
  • infinitive = want to
• debeo
  • infinitive = ought to / must
• audeo
  • infinitive = dare to

Here qui is best understood as a generic relative pronoun: the person who, whoever, or anyone who.

So:

• qui aliquid dicere vult = whoever wants to say something
• more literally, the one who wants to say something

It is not really pointing back to a specific noun stated just before it. Latin often uses a relative pronoun this way in general statements.

Aliquid is the neuter singular form of the indefinite pronoun meaning something.

In this sentence it is the object of dicere:

• aliquid dicere = to say something

Latin often uses aliquid as the neuter pronoun form meaning something / anything, especially when there is no specific noun attached.

By contrast, aliquod would usually be an adjective form meaning some with a neuter noun, for example:

• aliquod verbum = some word

But here there is no noun, so the pronoun aliquid is correct.

Because volo, velle means to want, and like English want, it regularly takes an infinitive:

• vult dicere = he/she wants to say
• volo legere = I want to read

So:

• qui aliquid dicere vult = whoever wants to say something

This is another example of the very common verb + infinitive pattern in Latin.

Amico is the dative singular of amicus, and here it means to a friend.

The dative is used for the indirect object, the person to whom something is said or whispered:

• amico susurrat = he/she whispers to a friend

So the structure is:

• something is whispered
• to a friend

That to a friend idea is exactly what the dative often expresses.

Tantum here means only or just.

So:

• amico tantum susurrat = only whispers to a friend

It limits the action: instead of speaking normally or shouting, the person just whispers.

Depending on how you take the emphasis, it can suggest:

• only whispers
• whispers only to a friend

Latin adverb placement is fairly flexible, so the exact shade of emphasis often depends on context.

Latin word order is much freer than English word order because Latin uses endings to show grammatical function.

For example, in:

• In bibliotheca nemo omnino clamare audet
• qui aliquid dicere vult, amico tantum susurrat

you can still tell what each word is doing from its form:

• nemo = subject
• clamare = infinitive
• amico = dative
• aliquid = object

Because of that, Latin can move words around for emphasis, rhythm, or style. English depends much more heavily on position.

The present tense here expresses a general truth or a habitual situation:

• nemo ... audet = no one dares
• qui ... vult ... susurrat = whoever wants ... whispers

This is not necessarily describing one single moment. It sounds more like a general rule about what happens in a library.

Latin often uses the present tense this way, just as English does.

Here susurrat is being used without an expressed direct object. The focus is on how the person speaks and to whom:

• amico susurrat = whispers to a friend

Latin susurro / susurro can be used with an object in some contexts, but it can also be used this way, where the whispered words are left unspoken because they are obvious from the context.

So the sentence does not need to say exactly what is whispered; it is enough to say that the person whispers to a friend.

The semicolon separates two closely connected ideas:

1. No one dares to shout in the library.
2. Anyone who wants to say something only whispers to a friend.

The second clause explains or develops the first. It shows what people do instead of shouting.

So the semicolon helps mark a strong pause while still showing that the two parts belong together.