for 2D clients at v3.x, you just simply delete/rename the file to something other than speech.mul
4.x Clients are freaky. I've found that some are causing massive problems with freezing (like 4.0.0l), so I am suggesting 4.0.0b since it crashes *less often* for me... and I do believe, that just simply deleting the speech.mul will work. Unless you are using Unicode... then I have no clue
3D clients, just don't work. I have yet to find a solution to 3D clients and speech.mul for any version of it. I don't even think POLHook as found a solution to that, as Folko doesn't have 3D installed to work on it
