La bibliografía está al final, pero antes quiero mejorar el diálogo y el monólogo de mi presentación sobre el argumento.

Because al final describes a location/position in the document or presentation, and Spanish normally uses estar for location.

• La bibliografía está al final = the bibliography is at the end
• estar is common for where something is placed

If you used es here, it would sound unnatural in standard Spanish.

Al final means at the end.

Al is the mandatory contraction of:

• a + el = al

So:

• al final = at the end
• not a el final

This contraction happens whenever a is followed by the masculine singular article el, except when el is part of a proper name.

Examples:

• Voy al cine.
• Está al final del libro.

Spanish often uses the definite article more than English does.

Here, la bibliografía refers to a specific section: the bibliography of the presentation or document. Using the article sounds natural and complete.

Compare:

• La introducción está al principio.
• La conclusión está al final.
• La bibliografía está al final.

In headings, you might see just Bibliografía, but inside a full sentence, la bibliografía is the normal choice.

Because antes can be used in two different ways:

1. Antes

   • main clause
   • Pero antes quiero mejorar...
   • Here antes means before that / first

2. Antes de

   • noun or infinitive
   • Antes de la presentación...
   • Antes de hablar...

So in your sentence, antes is being used on its own as an adverb, not followed directly by a noun or infinitive.

Examples:

• Antes quiero terminar esto.
• Antes de terminar, necesito ayuda.

Yes. After querer, Spanish normally uses an infinitive.

Structure:

• querer + infinitive

So:

• quiero mejorar = I want to improve
• quiero estudiar
• quiero hablar
• quiero cambiar el texto

This is very common and works much like English want to + verb.

Using both articles is the most natural and correct form here:

• el diálogo y el monólogo

Spanish often repeats the article when talking about two separate nouns, especially when you want to clearly mark them as two distinct things.

You may sometimes hear omitted repetition in some contexts, but here repeating el sounds better and more standard.

Compare:

• el padre y la madre
• el principio y el final
• el diálogo y el monólogo

Yes, the accent marks matter.

• diálogo = dialogue
• monólogo = monologue

The written accents show the stress:

• di-Á-lo-go
• mo-NÓ-lo-go

Without the accent marks, the spelling would be incorrect in standard Spanish.

The same is true for:

• bibliografía
• está

Accent marks in Spanish are not optional; they are part of correct spelling.

Here de means something like of:

• el diálogo y el monólogo de mi presentación
• = the dialogue and monologue of / in my presentation

It links the nouns to show possession or association.

So this part means that the dialogue and monologue belong to, or are part of, my presentation.

Spanish uses de very often where English might use:

• of
• possession
• a noun used attributively

Examples:

• el título de mi libro
• el final de la película
• la idea de Ana

Sobre means about / on the topic of, so:

• mi presentación sobre el argumento
• = my presentation about the plot / argument / theme

If you said de mi presentación del argumento, that would sound different and less natural in this context.

A useful contrast:

• presentación sobre X = presentation about X
• parte de X = part of X
• resumen del argumento = summary of the plot

So sobre is the natural preposition when the presentation’s topic is el argumento.

Not necessarily. Argumento is a word that can be tricky because it does not always match English argument.

Depending on context, argumento can mean:

• plot or storyline of a book, film, or play
• line of argument / thesis / reasoning
• subject matter in some contexts

In this sentence, sobre el argumento could mean:

• about the plot, if the presentation is about a story
• about the argument / reasoning, if it is an academic or persuasive presentation

So this is a word where context matters a lot.

The original word order is natural, but Spanish does allow some flexibility.

Original:

• La bibliografía está al final, pero antes quiero mejorar el diálogo y el monólogo de mi presentación sobre el argumento.

Possible variations:

• La bibliografía está al final, pero quiero mejorar antes el diálogo y el monólogo...
• Pero antes quiero mejorar el diálogo y el monólogo...

However, the original version is probably the clearest and most natural for everyday use.

Spanish often moves elements for:

• emphasis
• rhythm
• contrast

But if you are learning, the original order is a very good model to follow.

Yes, there is a small potential ambiguity.

Grammatically, sobre el argumento most naturally describes mi presentación:

• mi presentación sobre el argumento
• = my presentation about the plot/argument

So the structure is:

• el diálogo y el monólogo
  de mi presentación sobre el argumento

That means:

• the dialogue and monologue
• of my presentation
• which is about the argument/plot

In most contexts, this will be understood correctly. If you wanted to make the relationship even clearer, you could rephrase it, but the original is perfectly normal.

Because Spanish spelling marks stress very systematically.

In this sentence:

• bibliografía → stress on -fí-
• está → stress on -tá
• diálogo → stress on -á-
• monólogo → stress on -nó-

These accents help show pronunciation and distinguish correct written forms. For a learner, they are especially useful because they tell you where the word stress goes.

So when writing Spanish, it is important to include them:

• not bibliografia
• not esta
• not dialogo
• not monologo

The accents are part of the correct spelling.