Thank you. I changed it to the Americanized form of possessive for words ending in s (pronounced or not) I think this could go either way, but I screwed it up no matter which choice an author might take.
There is no fully agreed upon means make words ending s (x or z) into possessive - the below site gives example of Dumas' and Dumas's as valid.
My general response has been if it looks ok with just an ' leave it and move on. I can open my own shop with the left over apostrophes.
http://en.wikipedia.org/wiki/Apostrophe#Nouns_ending_with_si...
Still, I prefer my rendition. The problem here is the incompatibility between the rules of pronounciation -- French permits silent letters to end a word, English in general does not. In translating to English you must choose either to honour the French or the English rules of pluralisation and possession.
Because I don't write many English sentences with de la, du or d', I figure that sticking to the English rule is the best move.
edit:
> Jacqueses! (Jacuqi?)
Jacqueses would be closest (-ii is a Latin pluralisation, Jacques comes from Jacob which is Hebrew).
There's an impedance mismatch here: English stores plurality in the word, French stores it in the sentence.
Tiny, irrelevant nitpick.
Assuming that Jacques Mattheij is using the French pronounciation of his first name, the possessive version of Jacques is Jacques's.
This is because in French the final letter of most words is silent, and in English the possessive form of spoken nouns not ending in an audible "s" is rendered in text as <singular>'s.
Phoenetically:
Not: Regards,another Jacques.