I’m among those readers who need to know how a name is said when I am reading a book. Since I’m often asked about how to say Frevisse’s name, and sometimes about Joliffe, I thought a small note here may be welcome.
The trick with “Frevisse” is that it is the French version of “Frideswide”. Being French, it should probably be pronounced “fray-VEES”. But since she is in England and the English are infamous for what they do to French names, I say it as “FRAY-viss”.
I hasten to add that I have absolutely no objection to a reader pronouncing it the way they prefer. After all, England is a place of many dialects (and was in the 1400s, too), and there’s no reason you can’t claim “local usage” if your pronunciation differs from mine!
As for “Frideswide”, it is now pronounced “Fryswide” (with a long i in “wide”), but the spelling suggests that at some point the pronunciation was markedly different. (I say that any language that takes “Belvoir” and pronounces it “Beaver” can’t be trusted in any of its pronunciations.) So I pronounce it “Frid-es-wid” (with short i’s ), but equally possible in a medieval context it could be “Frid-es-WEEdah”. I suppose it depends on which side of the Great Vowel Shift you want to be on?
Then there’s Joliffe. For once, he is less trouble than usual. I pronounce his name with a short o and no final e. But if you prefer, it can be said with a long o. And even with the final e, I suppose.
As you can see, I am not strict about any of this. I suspect it’s all the reading I do in Middle English that has made my attitude toward pronunciation far more free-form than it once was. (Not to mention what havoc medieval spelling has made to my spelling.) So feel free to choose whatever slides easiest through your mind while you are reading and enjoy!