What kind of narrative language and dialogue style do you tend to use in your games?

For GMs:

Do you use poetic language to paint pictures with words and immerse the players in the setting? Or do you describe things in a straightforward way?

For players and GMs:

When your characters have conversations, how much of it do you act out and say the words your character would say, and how much is "I ask him if he has any jobs available."?

I'm trying to figure the right balance for myself--I want to paint an evocative picture for my players but it doesn't tend to come naturally.

I think it's something you need to balance with your group. One of my favorite GMs could have been a professional writer he was absolutely amazing and describing vivid descriptions of landscapes and NPCs. Unfortunately, he got frustrated and quit running because most of the group just wanted to get to the action and would keep interrupting him while he was trying to describe what was happening.

Personally, I try to give a little flavor with straight forward facts and keep it to 30-60 seconds otherwise the players drift off. I try to give a quick overview and then describe a few key features of the area or NPC. I got it from the FATE system and add Aspects to my scene and NPCs that help give an idea.

For example an encounter might happen in a warehouse and I would have already written down Aspects of: Dark corners, scattered debris, rusty catwalks.

I would say something like:

You enter a large warehouse approximately 100 x 50 yards. There are numerous large storage containers throughout the warehouse. You notice there is only a little natural light coming though broken skylights which is illuminating the central warehouse but creating DARK CORNERS and SCATTERED DEBRIS on the floor. You also notice RUSTY CATWALKS with stairs leading up to them on the west and east sides of the building.

It takes some planning but you can see writing down a few aspects for every scene can really help you describe it later. If you want more info check this link out.

http://fate-srd.com/fate-core/scenes-sessions-scenarios

As a GM, I only use very "poetic" language to set the initial scene of a gaming session. It tends to get players focused on the starting up the session after everyone has gathered, chatted and set up their game space.

After that, I'll just go straight forward in my descriptions. I only paint in the details which are important in a given environment and allow people to fill in the rest in their imagination.

For example, if I were describing a subway station, I really only need to describe the amount of people and the quality of the station (old and dingy, or new and polished). Most people will get a visual picture from there. I'll try to follow that up with an additional sense: a smell, sound, etc. (muffled traffic sounds from the street-level, or a sticky platform underfoot).

My advice is: don't overdo it. It's easier to be a minimalist since it's less prep time. Players will often ask questions about anything you didn't describe allowing you to refine your "painting" based on what your players want to see rather then what you're forcing them to notice.