Yes, that's how I would say it. JamZ (James) and JamZIZ (James's / James') This is what the MLA style guide says (American university standard style)...although you have probably already read this. "Note, though, that when a word ending in s is the same in the plural as it is in the singular, you just add an apostrophe: scissors’ blades identity politics’ critics Also add only an apostrophe for proper names when the name is plural but the entity is singular: the United States’ policy on China In MLA style, proper nouns ending in s that are singular follow the general rule and add ’s : Athens’s history Diogenes’s philosophy Alexandre Dumas’s novels Some styles may allow you to add only an apostrophe: Athens’ history, Diogenes’ philosophy, Dumas’ novels.

Hello again, Yes, you have understood correctly. The pronunciations on Vocaroo are correct. I was simply writing them how they sound for English speakers and not in IPA: JamZ [ʤeɪmz] and JamZIZ [ʤeɪmzi:z]. The possessive form is said [ʤeɪmzi:z] ( perhaps only with some accents [ʤeɪmi:z] as you wrote in your original message), no matter if it's spelled James' or James's. :-) I'm answering here because I can't seem to make a comment to you above. The system doesn't want to accept it.