Files are of type 0x808097B8
They contain similar/related dialogue. e.g. All of a strike's dialogue will be in one file.
The file has a top-level array of 0x80809729
blocks (which I call a "DialogueTree") which represents all the different dialogue groups of dialogue. e.g. Each "trigger" of dialogue in a strike will be one of these top level entries.
There is roughly a nested tree of three types of data:
0x8080972d
Branch, that describes random dialogue or condition-specific dialogue0x8080972a
Sequence, for a sequence of multiple lines of dialogue0x80809733
Line, an actual line of dialogue. caption, narrator, audio file