It doesn't seem to take into account any modifiers. For example, if I press the comma key (dvorak layout) it sounds the same regardless of wether I hold down the shift key (it then produces a < sign). It also claims to "take very little memory, CPU and disk space". This minor utility is 2.3MB large, takes 4MB of private resident memory and constantly consumes ~1-4% of CPU on my 1GHz G4.