OK, problem solved. Turned out I had made a bad rip of my original disc.

When I play Legend of Kyrandia 1 (DOS - CD version) on the PC port of ScummVM 0.11.1 I can hear speech when loading the game with default settings. However, when I load the same game on my PSP with CFW 3.71 M33, also with the same scummVM version and default game settings, I cannot get the speech to...