Well, the dialogue is not Old English. If it was, you would be unable to read it. The dialogue given to certain characters, e.g. Minfilia and Urianger, is an archaic form of Modern English. I do, however, agree with you. The archaic language seems rather forced or poorly translated from perhaps an archaic version of Japanese to an Archaic version of English, and it is not only the word choice that annoys me, but it is also the archaic syntax structures that give the dialogue of certain characters a less fluid and natural feel. In other words, the translators did a poor job of mimicking the syntax structures and word choice of sixteenth century English.