Soon I'm gonna start to write some movie scripts on English, so far they have only been on Croatian so I think I should practice writting dialogs and similiar things...
But anyway, my real question is about rules of writting scripts. When does a script stop being a script and what are the basic rules that I need to follow?
What are the most used phrases which represent the begging of a dialog or to show that the dialog is happening outside for example without mentioning it in the beggining of the description?
It can sound a little bit confusing but I'm not quite sure how to ask, hope somebody got it, thanks in advance.

Lmao i am a little confused with what you mean about "When does a script stop being a script". In my opinion a script is what you make it, but the format has to be dead on. If you are having problems with that there is information on this website about script format and so on.

Always start with Fade In:

Then either INT (internal - inside) EXT (external - outside) a dash -- then your location and whether it is either DAY or NIGHT. These are for the beginning of your scenes. For example.

EXT. CASTRONE FARM -- NIGHT

A desolate deprived barn is perched at the outskirts of the forrest.

Above is what you call the action in a script. This comes straight after your scene heading traditionally and sets your scene.

What then follows traditionally is your dialogue. Like so..

                                      TEDDY (V.O)
                       Pappa always told me never
                       to cry over spilled milk. Tell
                       you the truth, Pappa taught
                        me a lot of things.

The V.O signals voice over but that is a different story completely. Your font also has to be Courier size 12. If i didn't answer your question then can you ask again lol.

I'm also uncertain on what you mena, but I know what you're looking for. To put everything more simply, check this link for formatting info: http://www.simplyscripts.com/WR_format.html

For hwo a script looks, this site has a wealth of them to show you what one looks like. You can browse the unproduced ones, but if you're starting out, it is better to look through scripts where you can follow along with the produced movie. That is actually the best start for you.

Yeah, that's pretty much what I asked... Thank you both for reply's.
I was mostly thinking about the things like "INT", "EXT" and their meanings even though I presumed it. Is there any place where I can find a collection of them that are mostly used and the explainations?

I read the formatting info but it seems rather complicated for now, I believe that something that you correct when you finish the script.
I'm only concerned with the main rules for now, but anyway the link is great! Thx
If somebody has some other usefull links for beggings I would really appreciate it.

INT = Interior
EXT = Exterior

Quoted from SwapJack INT = Interior EXT = Exterior

Yeah... Got that, I'm not an idiot.  
I was asking for similiar words that are used.

There aren't any similar words. Well, there are similar terms for interior and exterior, but when you're writing a script you need to start each scene by indicating whether it is INT. or EXT.

INT. THE WHITE HOUSE

EXT. THE PARK

Only use INT. and EXT. Nothing else. That is one of the rules of screenwriter. I guess, you could say, if you don't then that's why your "script stops being a script."

Well, If that's the case then ok... I kinda thought more similiar terms were used, but anyway, thanks for clearing that up.

I'd also say that you could use "I/E." as the only on term to introduce a scene.  As you probably guessed, this means Interior/Exterior.

If you are just looking for terms in general, there's some for dialogue such as "V.O." for Voice Over (previously stated), "O.C." for Off Camera, and "O.S." for Off Screen.  The latter two of those I believe are just a preference as two which one to use as they mean basically the same thing.

Hope that helps.

-Pat