Die Vortragende bittet uns, leise zu bleiben.

Because Vortragende is being used as a noun here, not just as an adjective or participle.

German often turns adjective-like words into nouns this way:

• der Vortragende = the male presenter/speaker
• die Vortragende = the female presenter/speaker
• die Vortragenden = the presenters/speakers

When an adjective or participle is used as a noun, it is capitalized in German.

It is a substantivized participle/adjective.

It comes from the verb vortragen = to present, give a talk, deliver a lecture/presentation.

So vortragend originally means something like presenting. When German turns that into a noun-like form, it becomes:

• der Vortragende
• die Vortragende

So grammatically, it behaves like an adjective with adjective endings, but functionally it means the presenter / the speaker.

Because the word takes adjective endings, and the ending depends on gender, number, case, and article.

Here we have:

• die = definite article
• feminine
• singular
• nominative

With a definite article in feminine nominative singular, the adjective ending is -e.

So:

• die Vortragende = the female presenter

Compare:

• der Vortragende = masculine nominative singular
• die Vortragende = feminine nominative singular
• den Vortragenden = masculine accusative singular
• die Vortragenden = plural in some forms, or singular in some other cases

Yes, in this sentence it is read as singular feminine.

That is because:

• the article is die
• the ending fits feminine nominative singular
• the verb bittet is singular

So this means the female presenter/speaker.

If it were masculine, it would be der Vortragende.

bittet is the 3rd person singular present tense of bitten.

The subject is die Vortragende, which is singular, so the verb must also be singular:

• ich bitte
• du bittest
• er/sie bittet
• wir bitten
• ihr bittet
• sie/Sie bitten

So die Vortragende bittet = the presenter asks / is asking.

Because uns is the object form, while wir is the subject form.

The sentence pattern with bitten is:

jemanden bitten, etwas zu tun
= to ask someone to do something

So:

• die Vortragende = subject, the person doing the asking
• uns = the people being asked

That is why German uses uns, not wir.

A useful note: uns can be both accusative and dative in form, but with bitten it is accusative.

The pattern is:

jemanden bitten, ... zu + infinitive

So in this sentence:

• die Vortragende bittet = the presenter asks
• uns = us
• leise zu bleiben = to stay quiet / to remain quiet

This is a very common German structure.

More examples:

• Er bittet mich, zu warten. = He asks me to wait.
• Sie bittet euch, pünktlich zu sein. = She asks you to be on time.

Because leise zu bleiben is an infinitive clause with zu.

German often separates these clauses with a comma, especially when it helps make the structure clearer.

Here the comma marks the part that expresses what we are being asked to do:

• Die Vortragende bittet uns, ...
• ..., leise zu bleiben

In modern German, commas before infinitive clauses can sometimes be optional depending on the structure, but in sentences like this, using the comma is very common and helps readability.

Because in German, an infinitive clause with zu usually goes toward the end of the clause, and the infinitive itself is typically at the very end.

So the structure is:

• Die Vortragende bittet uns = main clause
• leise zu bleiben = infinitive clause

Within that infinitive clause:

• leise comes before the infinitive
• bleiben comes last

This end position is very normal in German.

Because bleiben means to remain / stay, and that fits the idea very naturally here.

• leise sein = to be quiet
• leise bleiben = to stay quiet / remain quiet / keep quiet

In a situation like a talk or presentation, German often prefers leise bleiben because it suggests continuing to be quiet or keeping quiet.

So it sounds more natural in context.

Here leise is used predicatively, after the verb bleiben.

That means it does not take an adjective ending.

Compare:

• eine leise Stimme = a quiet voice
  
  • here leise is before a noun, so it behaves like an attributive adjective
• Die Stimme ist leise. = The voice is quiet.
  
  • here leise is predicative, so no ending
• Wir sollen leise bleiben. = We should stay quiet.
  
  • same idea here

So in leise zu bleiben, leise stays in its basic form.

The understood subject is uns.

In other words, the presenter is asking us to stay quiet.

So although uns is the object of bittet, it is also the understood doer of bleiben inside the infinitive clause.

That is very common with verbs like bitten:

• Sie bittet uns, leise zu bleiben.
• She asks us to stay quiet.

We are the ones who are supposed to stay quiet.

Yes. German has several possible words depending on context:

• Vortragende = presenter / person giving the talk
• Referentin = speaker/presenter, often in a more formal or academic setting
• Rednerin = female speaker, often for speeches
• Dozentin = female lecturer/instructor

Vortragende is a natural choice when talking about someone giving a presentation or talk. It sounds a bit formal and is built in a very typical German way.