| Sorry this is so late, but that's a good question.
There should be a file in your /SOUNDS subdirectory called sndlist.txt. Here's what it says:
Customizing Icewind Dale Sound Personalities
============================================
The following is a list of the WAV files required to create custom sound personality sets. In the 'Sounds' folder located in the directory in which Icewind Dale is installed in, you will need to create a subdirectory that is used to store your new character personality. The new folder can be up to 32 characters in length. This folder will be displayed in the game as one of the voice set options. Below is a listing of all the required voice sounds that are needed in that new subdirectory. Replace the xxxxx with a unique name that would not be used in other subdirectories. For example, mysnd01, mysnd02, etc. As long as the xxxxx is unique, the voice sounds will show up and work properly in Icewind Dale.
All of the sound files must be 22 kHz, 16-bit, mono WAV files.
xxxxx01.wav : Morale Failure 1
xxxxx02.wav : Morale Failure 2
xxxxx03.wav : Battle Cry 1
xxxxx04.wav : Battle Cry 2
xxxxx05.wav : Battle Cry 3
xxxxx06.wav : Battle Cry 4
xxxxx07.wav : Battle Cry 5
xxxxx08.wav : Becoming Leader 1
xxxxx09.wav : Becoming Leader 2
xxxxx10.wav : Tired 1
xxxxx11.wav : Tired 2
xxxxx12.wav : Bored 1
xxxxx13.wav : Bored 2
xxxxx14.wav : Hurt 1
xxxxx15.wav : Hurt 2
xxxxx16.wav : Selected Common 1
xxxxx17.wav : Selected Common 2
xxxxx18.wav : Selected Common 3
xxxxx19.wav : Selected Common 4
xxxxx20.wav : Selected Common 5
xxxxx21.wav : Selected Common 6
xxxxx22.wav : Selected Common 7
xxxxx23.wav : Selected Action 1
xxxxx24.wav : Selected Action 2
xxxxx25.wav : Selected Action 3
xxxxx26.wav : Selected Action 4
xxxxx27.wav : Selected Action 5
xxxxx28.wav : Selected Action 6
xxxxx29.wav : Selected Action 7
xxxxx30.wav : Selected Rare 1
xxxxx31.wav : Selected Rare 2
xxxxx32.wav : Selected Rare 3
xxxxx33.wav : Selected Rare 4
xxxxx34.wav : Being hit 1
xxxxx35.wav : Being hit 2
xxxxx36.wav : Being hit 3
xxxxx37.wav : Dying 1
xxxxx38.wav : Dying 2
xxxxx39.wav : Reaction to partymember dying 1
xxxxx40.wav : Reaction to partymember dying 2
xxxxx41.wav : Critical hit 1 (Optional) --IWD2 only
xxxxx42.wav : Critical hit 2 (Optional) --IWD2 only
xxxxx43.wav : Falling Down (Optional) --IWD2 only  | 
Linear Mode
