Playing the game in english and the language listed in the weidu.conf is en_us.
and for clarification an example of specefically what happens is letsay at the beginning of the game, right after Imoen joins, I have the PC manually start dialogue with her, the textbox just says "INvalid:94293" and then gives me 7 responses "1:INvalid 94294", "2:Invalid 94296", "3:Invalid: 94297" and so on. If I walk over to where Gorion encountered the armored figure, Imoen starts a dialogue that just shows "INvalid: 82840" and my responses are also just invalid+number.
Vanilla dialogue works fine, such as conversations with IMoen or Khalid and Jahiera about joining, et cetera.