This is an extract taken from chapter VI, of Mark Twain's book "The Prince and the Pauper". I just can't understand the meaning of "unweighty trifle."
"I am full loth to word the thing that is in my mind, and thou so near to him in blood, my lord. But craving pardon if I do offend, seemeth it not strange that madness could so change his port and manner?--not but that his port and speech are princely still, but that they DIFFER, in one unweighty trifle or another, from what his custom was aforetime. Seemeth it not strange that madness should filch from his memory his father's very lineaments; the customs and observances that are his due from such as be about him; and, leaving him his Latin, strip him of his Greek and French? My lord, be not offended, but ease my mind of its disquiet and receive my grateful thanks. It haunteth me, his saying he was not the prince, and so--"