Learn Hardcore Turkish: Biz, birlikte çalışarak bu işi bugün bitirmek üzereyiz. - By working together, we are about to finish this job today.

bitirmek üzereyiz = we are about to finish / on the verge of finishing (imminent, almost done now).
bitireceğiz = we will finish (plan/intention about the future).
bitiriyoruz = we are finishing (ongoing action; doesn’t necessarily imply “almost done”).

Why is the infinitive bitirmek used before üzereyiz?

Because the postposition üzere requires the verb in the -mek/-mak infinitive form. The structure is: Verb-(m)ek + üzere + personal ending. Here: bitir-mek üzere-yiz.

How do I conjugate this -mek üzere pattern for different persons?

I: bitirmek üzereyim
You (sg): bitirmek üzeresin
He/She/It: bitirmek üzere
We: bitirmek üzereyiz
You (pl): bitirmek üzeresiniz
They: bitirmek üzere(ler) (the plural suffix is optional here; most often just üzere)

How do I make it negative or ask a question?

Negative: insert değil after üzere.
- bitirmek üzere değiliz = we are not about to finish
Yes/no question: use the question particle after the predicate.
- bitirmek üzere miyiz? = are we about to finish?
- Negative question: bitirmek üzere değil miyiz?

What does çalışarak mean, and how is -arak/-erek used?

-arak/-erek is a converb meaning “by/through V-ing” or “while V-ing,” often expressing manner or means. çalış- + -arak → çalışarak = “by working.” Vowel harmony applies: after back vowels use -arak, after front vowels use -erek (e.g., gülerek, konuşarak).

Could I use çalışıp or çalışırken instead of çalışarak?

çalışıp (with -ıp/-ip) suggests sequence: “work and (then) … finish.” Slightly less “by means of,” more “and then.”
çalışırken = “while working” (time relation), not “by working.” For “by working together,” çalışarak is the most natural choice.

Is birlikte necessary, or is it redundant with çalışarak?

It’s not redundant. çalışarak = “by working,” while birlikte adds “together.” So birlikte çalışarak = “by working together.” A near-synonym is beraber: beraber çalışarak.

Is the comma after Biz, correct?

A comma after a simple subject is not standard here. Write it without the comma: Biz birlikte çalışarak… The comma would only be used if there were a parenthetical or a special pause.

Do I need the subject pronoun Biz at all?

No. The ending -yiz already marks “we.” You can simply say: Birlikte çalışarak bu işi bugün bitirmek üzereyiz. Use Biz only for emphasis (We, as opposed to others).

Why is it bu işi (accusative) and not just bu iş?

Because the direct object is definite/specific. In Turkish, definite objects take the accusative -(y)i. Since it’s “this job,” it must be bu işi. The rule still applies even though bitirmek is in the infinitive: compare Okulu bitirmek istiyorum (“I want to finish school”).

Can I change the word order? For example, put bugün earlier?

Yes. Common options:

Bugün bu işi birlikte çalışarak bitirmek üzereyiz. (time up front)
Bu işi bugün birlikte çalışarak bitirmek üzereyiz. (object up front)
Birlikte çalışarak bugün bu işi bitirmek üzereyiz. (manner up front) All are grammatical; moving elements changes what you foreground. Turkish often places time adverbs like bugün early.

Could I use için instead of üzere?

Different meaning:

… bitirmek üzereyiz = we are about to finish.
… bitirmek için çalışıyoruz = we are working in order to finish. So için expresses purpose; üzere here expresses imminence.

Is … üzereyiz formal? What are colloquial alternatives?

It’s neutral to slightly formal. Colloquial alternatives:

Neredeyse bitirdik. (We’ve almost finished.)
Bitirmeye çok az kaldı. (There’s very little left to finish.)

Can you break down the sentence morphologically?

Biz = we (subject pronoun)
birlikte = together (adverb)
çalış-ara-k = work + converb “by/while V-ing”
bu = this (demonstrative)
iş-i = job/work + accusative -(y)i (definite object)
bugün = today (time adverb)
bitir-mek = to finish (transitive infinitive)
üzer-e-yiz = on the point of + 1pl copular ending; buffer y appears because both sides are vowels

Is there any difference between bitirmek üzereyiz and expressions with olmak, like … üzere olmak?

Dictionaries list it as -mek üzere (olmak), but in use you normally attach person directly: bitirmek üzereyim/üzereyiz. You don’t need an explicit olmak here—the personal ending already supplies “to be.”

Is there any stylistic issue with saying both birlikte and çalışarak?

No. birlikte specifies “together,” and çalışarak gives the means (“by working”). The phrase birlikte çalışarak is idiomatic and clear.