The settings defined at IFC Local Preferences (File > Interoperability > IFC) affect the way that IFC data are created and managed.
IFC Interface language
The language of the IFC standard/code is English, thus the default and recommended setting for the interface is English. In localized ARCHICAD versions, some standard IFC key words (such as IFC Entity, Property, Attribute names) may be shown in the local language, but this has no effect on the IFC export, just helps users comprehend IFC terms on the interface.
Save Library Parts Generated During Import To
Set the default location of imported Library Parts when opening or merging an IFC project.
Express Data Manager (EDM) path
The EDM (Express Data Manager) toolkit is the engine which creates an ARCHICAD model from the imported IFC model, and which also creates an IFC file out of the exported ARCHICAD model. The default engine is the recommended one, but you can use the Redefine option here to modify it as needed.