I think the intros would be best without any audible narration, unless someone has enough balls to pronounce them in the faction's native language. It would be a little weird that the only English you'd hear in game were in the intros. The only English voices in EB at the moment are the campaign map ones, the pre-battle speeches and the Greek and eastern "Run to deh hillz!", which will most likely be phased out in the future. Just a simple text narration would be the best and easiest in my mind.
An out of topic question for all the modders out there:
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