We had someone ask us recently whether, in referring to multiple of us in the Evans family, it should be "Evans" or "Evanses". I know the rule for possessive; since it is a two syllable word and ends in an "s", you just add an apostrophe if speaking of the Evans' house, the Evans' dog, etc. But what if someone isn't talking about our things, but about the plural us? As in, "those wonderful Evans(es)"? I did some research and found this:
When a family name (a proper noun) is pluralized, we almost always simply add an "s." So we go to visit the Smiths, the Kennedys, the Grays, etc.When a family name ends in s, x, ch, sh, or z, however, we form the plural by added -es, as in the Marches, the Maddoxes, the Bushes, the Rodriguezes. Do not form a family name plural by using an apostrophe; that device is reserved for creating possessive forms.
When a proper noun ends in an "s" with a hard "z" sound, we don't add any ending to form the plural: "The Chambers are coming to dinner" (not the Chamberses); "The Hodges used to live here" (not the Hodgeses). There are exceptions even to this: we say "The Joneses are coming over," and we'd probably write "The Stevenses are coming, too." A modest proposal: women whose last names end in "s" (pronounced "z") should marry and take the names of men whose last names do not end with that sound, and eventually this problem will disappear.
Since I failed to follow their suggestion and instead went from a rather simple last name with no troublesome s's at all to one with various rules and too many exceptions, I must now pay the price and try to resolve this. So we Evans(es) end in an "s", but with the "z" sound, so we fit the second rule; but the exception examples of Jones and Stevens sound an awful lot like Evans, so we're back to square one. I think, after this inconclusive research, either way would probably be correct! I will defer to my husband on his preference for the additional "es", since he's had the name longer and has a greater vested interest ;-)