Hello, some inputs,

I will assume that in your list each post is doing is only job (the concept artist doesn't model anything, the audio/sound artist doesn't implement the sound, etc...) In little studios, a person may have to works on many aspects on the games. (3d modeling and level designer and programming, etc...)

-The Level designer draws and models the levels

The level designer if he is only level designer, doesn't draws or model anything. He "just" use the models made by the artists (environnementals, characters, props) and the objects implementing the game mechanics (a door, some anchor to climb a wall) to put them in the level. In the case of UDK, thy may also use the matinee and kismet system.

Is there a specialty programmers who only program multiplayer games?

If you mean that is there programmer, whose work is only on working on the multiplayer aprt of your game, then I would say it depends on your organisation. In big studios with a lot of people yes, they can afford (and sometimes they must) have one programmer dedicated entirely on multiplayer programming. Not so much in little project :)

Will the programmers be able to work on a single project?

...I don't understand your question. I think it's more easy to works on a single project, than on multiple...

Does this project need to have a certain and single programming language?

Depends on the game engine you will chose. UDK uses either C++ or its own language, the unreal script. And flash for the UI. If you want to start your own engine, then most people will recommend you C++ (mother of all languages)


I think I can get your point. You want to know what is the workflow for making a game? You want to know how all the people in the project will interact wit each other?
If this is effectively your question, then there is a lot of way of doing it, and it's kind of complex.

The short version would be something like :

Game designer design the game.
Artists make the drawing, the models and all the ressources,
Programers Implement the mechanics.
Level designer create the levels by using the artists's ressources and programmer's mechanics
Game designer adjust the mechanics value.

Maybe.

Also, I don't know if you intended to make an exhaustive list of post needed in a video game project, but you are missing some posts. Lead programmer, Character designer, environmental artists, project leader, Q.A Tester, creative director, writers, and so on. But, as I said earlier, depending on the size of the project, there can be one person for multiple posts. :)