If this exchange took place in 1350 AD, the English language would have been in its Middle English phase. The phrasing would be quite different from modern English. Here's a possible rendition of that dialogue:
Character 1: "Art thou afeerd, Ser?" Character 2: "Worse. Ich am racionel."
Middle English had a variety of dialects and spellings were not standardized, so there could be some variation in how it was written or spoken. However, this gives a sense of how the conversation might have sounded during that period.