یکی از همکارهای من دارد روی یک پروژه جدید کار میکند.

یکی از is the normal Persian way to say one of.

• یکی = one / someone
• از = from, but in this pattern it works like of

So:

یکی از همکارهای من = one of my colleagues

You need از here for the partitive idea. Saying یکی همکارهای من would not be correct.

The base word is همکار = colleague.

To make it plural in everyday Persian, you add ها:

• همکار = colleague
• همکارها = colleagues

In همکارهای من, the ی is there because the phrase continues with من and is linked by ezafe. So this is basically:

• همکارها = colleagues
• همکارهای من = my colleagues

It is pronounced roughly hamkâr-hâ-ye man.

In Persian, possessors usually come after the noun, not before it.

So Persian says something like:

• همکارهای من
• literally: colleagues of me
• natural English: my colleagues

This is very normal Persian structure. English says my colleagues; Persian usually says colleagues + my.

Persian usually prefers Subject–Object/Complement–Verb order, so the verb often comes near the end.

This sentence is structured like:

• یکی از همکارهای من = subject
• دارد = progressive marker / auxiliary
• روی یک پروژه جدید = prepositional phrase
• کار می‌کند = main verbal idea

So Persian naturally puts the main verb later than English does.

Because Persian is expressing an ongoing action: is working.

• دارد literally means has, but here it functions like a progressive auxiliary: is currently
• کار می‌کند = works / does work

Together:

دارد ... کار می‌کند = is working

Also, کار کردن is a very common compound verb in Persian:

• کار = work
• کردن = to do

So کار می‌کند literally looks like does work, but it simply means works.

Yes.

You could say:

یکی از همکارهای من روی یک پروژه جدید کار می‌کند.

That is also correct. Without دارد, the sentence is less explicitly progressive. Depending on context, it can mean:

• one of my colleagues works on a new project
• one of my colleagues is working on a new project

Adding دارد makes the right now / ongoing meaning clearer.

روی literally often means on, and with کار کردن it is the normal way to say work on something.

So:

• روی یک پروژه کار کردن = to work on a project

This is an idiomatic, very common Persian pattern.

It does not mean physically standing on top of the project. It is just the standard way to express the idea of working on a task, plan, or project.

یک means one or a/an.

Here it gives the noun an indefinite meaning:

• یک پروژه جدید = a new project

Without یک, the phrase can become more general or depend more heavily on context. In a sentence like this, using یک is very natural if you mean a new project.

In Persian, adjectives usually come after the noun.

So:

• پروژه جدید
• literally: project new
• natural English: new project

That is the normal Persian order.

Yes. Even though it is often not written in casual typing, there is an ezafe link in pronunciation.

So:

• written casually: پروژه جدید
• pronounced: proje-ye jadid

In more careful writing, you may see it written more explicitly, such as:

• پروژهٔ جدید
• or پروژه‌ی جدید

The same thing is happening in همکارهای من: there is also a linking sound there.

Because پروژه is not acting here as a direct object by itself. It is inside the prepositional phrase:

روی یک پروژه جدید = on a new project

The marker را is used for direct objects, especially specific ones. But here Persian is using the structure work on X, not do X directly.

So no را is needed.

It is fairly natural and neutral, but it mixes slightly different levels of style.

For example:

• همکارهای sounds everyday and conversational
• دارد and می‌کند are standard written forms

A very spoken version might be:

یکی از همکارای من داره روی یه پروژه جدید کار می‌کنه.

A more formal version might be:

یکی از همکاران من روی یک پروژهٔ جدید کار می‌کند.

So the original sentence is perfectly understandable and natural, but not at the extreme formal or extreme colloquial end.