Apostrophe With Possessive Plural And Surname Ending With 's'

[catmando]

I have friends whose surname is Davies. They have a black car. What is the correct use of the apostrophe if you substitute my friends' surname for Robinson in the following sentence:
The Robinsons' car is black.
Is it Daviess' which to me looks wrong, Davies' which I believe is correct for Davies in the singular, Davies's or none of the above?

[Quizmonster]

TCL, as in "Keeping up with the Joneses", if the surname ended in 's' or an 'ess' SOUND such as with Cox, then it was usually pluralised by adding 'es'; hence, Crosses, Glasses, Blisses and Coxes, Lennoxes, Willoxes and so on.
With names ending in a vowel SOUND, such as Kennedy, only an 's' would be added, giving Kennedys rather than Kennedies, which woul be used only for the surname Kennedie, if such a thing existed!

[THECORBYLOON]

QM, a word ending in a "y" without a preceding vowel is pluralized by changing the "y" to "ies" which is why I mentioned Kennedies since that should be the plural if Joneses is the plural of Jones. Why should the rule for a name be different from that for any other word?

[jno]

I think it's "proper nouns" generally, TCL, which are thought too precious to alter. The French would go further and call them les Kennedy.

[THECORBYLOON]

That should be why is the plural of Kennedy not Kennedies as that follows other "y" words and why is it different?

[Quizmonster]

Adding an 's' to Kennedy, giving, Kennedys, is no different to adding an 's' to Smith, giving Smiths. By making them the Kennedies, you are losing the very basis of the name and names are just "different" as far as their owners are concerned, TCL!
I'm pretty sure the Sony company wouldn't be too happy if people said with referemce to TV sets, say, "I always buy Sonies" rather than "I always buy Sonys."

[lankeela]

I write reports on dog shows and we have an exhibitor called Davies. I always write the winner was Mrs Davies' dog. When Mr and Mrs Simpson win its the Simpson's dog.

[Quizmonster]

Lankeela, your second sentence is perfectly correct, because "Mrs Davies" is singular. In such a case, you may write either "Mrs Davies's dog..." or "Mrs Davies' dog..." as I explained in an earlier answer above.
However, your third sentence is simply wrong because "Mr and Mrs Simpson" is plural - ie it involves two or more people - and when we refer to them as a family unit, we call them "the SimpsonS" not "the Simpson". As a result, we would write, "the Simpsons' dog..."

[Bert]

Olg Geezer wrote:
"They would collectively be known as the Robinson family. You would say that the Robinson's car is black. You would say "ladies' bicycles don't have a crossbar."
Mr and Mrs Davies would be known as the Davies family, so it would be the Davies' car that is black."
Still wrong, Old Geezer. Mr and Mrs Robinson and any offspring could indeed be known collectively as the Robinson family. You might say that the Robinson family's car is black. However, they could also be known as the Robinsons (Just like the Joneses), in which case you would say that the Robinsons' car is black.
Words ending in -s or an s sound (like -x), or other sounds such as -ch and -sh generally add -es to form the plural, simply because it would be impossible to pronounce the plural written with only an s. Try to pronounce boxs, churchs, or fishs. The written form reflects the pronunciation. Some words do not change in the plural, e.g. sheep. Fish can stay the same in the plural or become fishes. Mr and Mrs Davies may stay the same in the plural (the Davies) or become the Davieses. In the first case, the car would be the Davies's car; in the second it would be the Davieses' car. The pronunciation would be the same.