In the text box you can faintly see the character's name, but not the dialogue. Tested on 1.5.0-926, hardware and software mode with different settings. This may only apply to the NTSC-J version, I don't have any others for testing.
Looking at the wiki entry for this game, it seems to be an unsolved problem from 0.9.7: http://wiki.pcsx2.net/index.php/Eternal_Poison
If anyone has found a solution since then I'd love to know, thanks
EDIT: I attached a GS dump just in case