Officially, the localized sound files were removed from the 8193.16 hotfix, current game version, because they were crashing players not using the default English players in the huge 8193.15 patch that came out the day before.
In your case, the French files in 8193.15 were being used instead of the English files, which sounds like a good thing, but what had happened is that they were used INSTEAD of the English files, and not "as well as". Since there wasn't an entire game's worth of French files (French tilesets, French spell VFX, French Skyboxes? Etc), the game was crashing.
This has been fixed in the 8193.17 development patch available for public testing, however, it is only available in Steam and the Beamdog Client. An update to the game with this fix will be in the next normal patch.
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In your case, the French files in 8193.15 were being used instead of the English files, which sounds like a good thing, but what had happened is that they were used INSTEAD of the English files, and not "as well as". Since there wasn't an entire game's worth of French files (French tilesets, French spell VFX, French Skyboxes? Etc), the game was crashing.
This has been fixed in the 8193.17 development patch available for public testing, however, it is only available in Steam and the Beamdog Client. An update to the game with this fix will be in the next normal patch.