I\'m dealing with game dialogue files (conversation between player and non-playable-characters) where dialogue choices and their outcome depend on certain conditions and res
If you haven't heard of YAML, have a look at it. It's like XML, but XML isn't really made to be written by hand--it's a machine-machine interface that happens to be human-readable (so you are really supposed to create an editor for it). YAML is a human-machine interface, much more writable.
I wouldn't bother with a DSL, YAML maps perfectly.