I wasn’t really sure how to answer this. Is the dual pronoun ever used to refer to two antagonists in Old English? I suppose one could say that the dual pronoun is sometimes used when the dual number of the referent is specifically regarded, not only because of intimacy. Sometimes the dual is conspicuous by its absence; for instance Adam and Eve are not refered to using dual pronouns in Ælfric’s translation of Genesis.
But what of other languages? I know that Old Norse also preserves the dual pronouns. What other languages do? Is there any special implication in the use of the dual in those languages (other than simply number)?
I’ve studied some languages with duals, but never paid enough attention to the circumstances under which they were used to be able to answer the question; anybody have any thoughts on the subject?