Nawet jeśli raport jest długi, chcę przeczytać go do końca jeszcze dziś.

Nawet jeśli means even if.

It introduces a condition that does not change the speaker’s intention:

• Nawet jeśli raport jest długi, chcę przeczytać go do końca jeszcze dziś.
• Even if the report is long, I want to read it to the end today.

A very close variant is nawet jeżeli. In everyday Polish, jeśli and jeżeli are usually interchangeable, though jeżeli can sound a bit more formal.

Because nawet jeśli raport jest długi is a subordinate clause, and in Polish subordinate clauses are normally separated by a comma.

So the sentence is divided like this:

• Nawet jeśli raport jest długi, = subordinate clause
• chcę przeczytać go do końca jeszcze dziś. = main clause

This is very standard Polish punctuation.

Because raport is a masculine singular noun, and the adjective must agree with it.

• raport = masculine singular
• długi = masculine singular adjective form

Compare:

• długi raport = a long report
• książka jest długa = the book is long
• zadanie jest długie = the task is long

So długi matches the gender and number of raport.

Because raport is the subject of jest długi.

In raport jest długi:

• raport = subject, so nominative
• jest = is
• długi = predicate adjective agreeing with the subject

This is similar to English: the report is long.

Because przeczytać is the perfective verb, and it emphasizes finishing the reading.

• czytać = to read, to be reading, to read in general/imperfective
• przeczytać = to read through, to finish reading/perfective

Here the sentence includes do końca and jeszcze dziś, both of which fit the idea of a completed action. The speaker wants not just to spend time reading, but to finish the report today.

So:

• Chcę czytać raport = I want to read/be reading the report
• Chcę przeczytać raport = I want to read the report completely / finish reading it

Go means it.

It refers back to raport:

• raport = the report
• go = it

So:

• chcę przeczytać go = I want to read it

This is the accusative form of the pronoun referring to a masculine noun like raport.

You absolutely can say chcę przeczytać raport.

Both are correct:

• chcę przeczytać raport = I want to read the report
• chcę przeczytać go = I want to read it

Using go avoids repeating the noun and sounds natural if raport has already been mentioned in the sentence.

Polish often repeats less than English by using pronouns like this, especially when the referent is already clear.

That is a very natural word order in Polish.

• chcę przeczytać go do końca
• literally: I want to read it to the end

You may also hear other orders, such as:

• chcę go przeczytać
• go chcę przeczytać (more marked, with emphasis)

But przeczytać go is completely normal.

Polish word order is more flexible than English, but different orders can slightly change emphasis. In a neutral sentence like this one, przeczytać go works well.

Do końca means to the end or all the way through.

In this sentence, it means the speaker wants to finish the report completely, not just read part of it.

Common examples:

• obejrzeć film do końca = watch the film to the end
• wysłuchać do końca = listen to the end
• przeczytać książkę do końca = read the book to the end

So przeczytać go do końca means read it all the way through.

Jeszcze dziś means something like:

• still today
• before today ends
• later today
• as early as today, depending on context

In this sentence, the most natural idea is:

• I want to finish reading it today, before the day is over.

Jeszcze often adds the idea of still / yet / before it’s too late / sooner than expected, and dziś means today.

So jeszcze dziś is stronger than just dziś. It suggests some urgency or determination.

Yes. Dziś and dzisiaj both mean today.

So these are both correct:

• jeszcze dziś
• jeszcze dzisiaj

The difference is mostly stylistic:

• dziś is a little shorter and sometimes slightly more literary or compact
• dzisiaj is very common in everyday speech

In this sentence, jeszcze dziś sounds very natural.

Because after chcę (I want), Polish uses the infinitive.

So:

• chcę przeczytać = I want to read
• chcę zrobić = I want to do
• chcę iść = I want to go

You do not use a second finite verb after chcę in this structure.

So chcę przeczytam is not grammatical.

Yes. Starting with Nawet jeśli... puts the possible obstacle first:

• Even if the report is long...

This highlights the contrast:

• the report may be long
• but that does not change the speaker’s plan

You could rearrange the sentence:

• Chcę przeczytać go do końca jeszcze dziś, nawet jeśli raport jest długi.

That is also correct, but the original version foregrounds the condition more clearly.

Yes, it is natural and correct.

A Polish speaker might also say slightly different but equally natural versions, for example:

• Nawet jeśli raport jest długi, chcę przeczytać go do końca jeszcze dzisiaj.
• Nawet jeśli raport jest długi, chcę go przeczytać do końca jeszcze dziś.
• Choć raport jest długi, chcę przeczytać go do końca jeszcze dziś.

The original sentence is fully idiomatic and sounds like normal Polish.