RPG/Adventure games are dependent on in-game dialogue for several purposes.
1) To instruct player how to play the game/use controls
2) To guide the player in the right direction to win the game
3) To enrich the story and build character empathy.
4) To immerse the player into the game
5) For humor
6) For game event triggers

Types of Dialogue used are:
1) Instructional- explains rules of a mini-game or game controls
2) Story based- dialogue to move the story.
3) Random Banter - environmental dialogue spoken by background NPCs

Dialogue is usually need-based in a game. For a visual medium like a game it is better to SHOW than TELL. If you can make an obvious visual cue, then do not use dialogue to explain it.

Cheesy example:
Bad: "I will wear my purple hat to battle you".

Better: "I wear my favorite hat to battle you"�.

Better yet: "This purple hat, which makes me stronger, will help me defeat you in battle."�

Best: *figure puts on purple hat*

The Bad example is something that can clearly be shown and does not need to be reiterated as text.

The Better example had a tiny bit of story element to it. That's why it was better.

The Better Yet example informed the player the effects the hat would have on that character.

In the Best example, the hat had no story value or stat effects on the character.

Basically, stating the obvious type dialogue is unnecessary.


-Using Branching Dialogue-
Branching dialogue is hard to write because it is difficult to keep track of what choices lead where and what choices trigger what event.

There are several tricks/cheats for branching dialogue.

Communist - really isn't branching dialogue, but you give the player a yes or no option. They actually HAVE to choose "yes" to continue in the game but hey, they could choose "no" if they want to.

Two-Fold-Path - Fairly simplistic dialogue where there are only two main branches to follow. There may be multiple choices but it ultimately leads down one of the two branches set up. For a generic example you could have the "Good" path or the "Evil" path. The choices in dialogue lead the character to a specific ending for the game. This is best for "multiple" endings...if you only have two options.

Multi-path - While the player may end up with the same result no matter what he/she chooses, the answers they pick could affect some in-game status and affect events later in the game. This is better described in an example:
You talk to Friend A and are given 3 responses. If you choose response 1, you gain +1 points with Friend A. Friend A responds with Generic Response B.
If you choose response 2, you gain 0 points with Friend A. Friend A responds with Generic Response B.
If you choose response 3, you lose 1 point with Friend A. Friend A responds with Rejected Response.

Later in the game:
If you chose response 1 or 2, Friend A comes to help you.
If you chose response 3, Friend A will betray you.

The Best example would be choices in a Dating Sim. It affects the ending of the game and events within the game. This is similar to Two-fold except there could be more than 2 endings.

Winding Path - This is best exemplified in a game like Neverwinter Nights or Fable. The dialogue is dynamically affected by character type and attributes and several layers of conditions.
It drives the player to a specific end based on their choices. This is different than Multi-Path in that it is not always clear what the result of decisions will be. (Unless you are familiar with the system.) It could affect environment, party members, your appearance, not just game ending.

For most RPGs it's best to stick with simpler forms of the branching dialogue.

Planning out branching dialogue is a complicated process in itself. It is a good idea to map out the "branches" using a flow chart method.

(An example of Branching Dialogue - Multi-path)

-Dialogue Length-
Cut-scene style dialogue should only be as long as needed to tell the story and/or give the player the information they need.

Unlike a book, players do not expect to read a lot while playing a game. You also don't want to write more than you need to.

It is really the best judgment of the writer what is necessary or not. But things like stating the obvious would be unnecessary. And if there's going to be a long soliloquy, make things visually interesting at least!

Also when displaying dialogue. Keep it to two lines of text on the screen at a time. Less it better. Break up long descriptions into chunks of two or three lines.
//end

(Just tips and common sense really. Could be combined with other articles on Dialogue...I have a lot.)