Dialogs.bin respectively Dialogs_DD.bin stores the subtitles in HD2. There's a file for each language. It is located in Hidden & Dangerous 2\Text\LANGUAGE\

Header Edit

32-bit INT file size
sub-block C509
32-bit INT block length
32-bit INT unknown, always 0100 0000

Subtitle n Edit

Each subtitle n has following structure:

Block C609 action example
32-bit INT block length -
sub-block C709
32-bit INT block length -
32-bit INT subtitle id 990000 (301B 0F00)
sub-block C809
32-bit INT block length -
STRING subtitle text So you made it this far? Well done. My name's Blair. I hope you like the weather we've laid on for you.
end string marker - 0