
The voices.idx and voices.dat files for the expansions may be the fault, they are only 1KB in the translated Steam version, but are a lot larger in the various translated boxed/retail versions. Presumably this is caused by packaging and distributing the wrong files, as these issues are not present in the english steam version or any of the non-english retail/boxed versions.

This happens across the board for most factions in all four expansions but only in the non-english versions. When clicking models on the world map like generals, captains, priests, etc. The easiest way to reproduce is to change language to german (Or any other non-english) and start a Teutonic Campaign as the Teutonic Order. The issue is: The non-english localizations of Total War: Medieval II - Definitive Edition on Steam ships the Kingdoms Expansions with missing voices. (I allready went through the basics with SEGA Support: Veryfing game files twice and checking if the DLC are enabled in steam.)

SEGA Support and Feral Interactive Support directed me here.
