Divine Divinity wasn't fully voiced (and there was a lot less dialogue in general), and the publishers for other localisations handled the voice acting.
Of course it is possible to voice other languages, but the pipeline for doing the motion capture, animations and processing is currently being developed and updated, and there is a delay before text is finalised and then gets translated. Whatever the cost benefit analysis is of other languages, adding any at the same time would be an additional level of complexity to the project.
