Antes de entregar la redacción, reviso la ortografía y compruebo si falta alguna coma.

After antes de, Spanish normally uses an infinitive when the subject of both actions is the same.

Here, the same person does both things:

• entregar the essay
• revisar and comprobar things before that

So antes de entregar is the natural structure.

A useful rule:

• antes de + infinitive = before doing something
• antes de que + subjunctive = before someone else does something

Example:

• Antes de salir, cierro la ventana. = Before leaving, I close the window.
• Antes de que salgas, cierra la ventana. = Before you leave, close the window.

In this context, redacción means a piece of writing such as a composition, essay, or written assignment.

In Spain, this is a very common school-related word. So here it does not mean something like editorial office or newsroom. It means the text the student has written and is about to hand in.

Spanish often uses the definite article where English would use no article or a possessive.

So:

• la redacción = the essay / the composition
• la ortografía = the spelling

In English, you might naturally say I check spelling, but Spanish usually prefers reviso la ortografía.

Also, Spanish often uses the article instead of my/your/his when the context is already clear. Here, it is obviously the spelling of that piece of writing.

Because Spanish usually omits subject pronouns when they are not needed.

The ending -o in reviso already tells you the subject is I:

• reviso = I check/review
• compruebo = I check/verify

You can add yo for emphasis or contrast, but it is not necessary:

• Yo reviso la ortografía, pero él no.

Without emphasis, leaving out yo sounds more natural.

Both can be translated as to check, but they are not exactly the same.

• revisar often means to review, to look over, or to check carefully
• comprobar often means to verify or to make sure

So in this sentence:

• reviso la ortografía = I review/check the spelling
• compruebo si falta alguna coma = I check whether a comma is missing

That combination sounds very natural: first a general review, then a specific verification.

Because comprobar is a stem-changing verb.

In the present tense, the o in the stem changes to ue when the syllable is stressed:

• compruebo
• compruebas
• comprueba
• comprueban

But:

• comprobamos
• comprobáis

This is a very common pattern in Spanish. Other verbs behave similarly, such as:

• encontrar → encuentro
• volver → vuelvo

So compruebo is the correct first-person singular present form.

Here si means whether or if in an indirect question:

• compruebo si falta alguna coma = I check whether any comma is missing

This si does not take an accent.

Compare:

• si = if / whether
• sí = yes

Examples:

• No sé si viene. = I don't know if he is coming.
• Sí, viene. = Yes, he is coming.

So in your sentence, si introduces the idea being checked.

Here alguna coma is best understood as any comma or some comma.

Spanish often uses algún / alguna in this kind of context when the speaker means at least one, without identifying a specific one.

So:

• si falta alguna coma = whether any comma is missing / whether there is some missing comma

It does not mean one particular known comma. It means one or more possible missing commas, viewed individually.

Also, alguna agrees with coma, which is feminine singular:

• algún error
• alguna coma

Because the sentence is structured around the idea whether any single comma is missing.

So alguna coma is grammatically singular, and the verb agrees with it:

• falta alguna coma

This is very natural in Spanish.

You could also say:

• compruebo si faltan algunas comas

But that sounds a bit more like you think there may be several missing commas.

The original sentence is more neutral and idiomatic: it checks for the possibility that some comma may be missing, without focusing on number.

Because Antes de entregar la redacción is an introductory phrase, and Spanish often separates that kind of phrase from the main clause with a comma.

So the structure is:

• introductory time phrase: Antes de entregar la redacción
• main clause: reviso la ortografía y compruebo si falta alguna coma

This comma helps mark the pause and makes the sentence easier to read.

With very short introductory phrases, Spanish sometimes omits the comma, but here the comma is very natural and stylistically good.

Yes, most likely.

The present tense here can describe:

• a habit
• a routine
• something the speaker usually does before handing in an essay

So the sentence suggests something like:

• Before handing in the essay, I check the spelling and see whether any comma is missing.

Spanish uses the present tense very naturally for routines and general procedures. In many contexts, it can also refer to a near-future action, especially when the time reference is already clear.