The following question may seem to belong in a math lesson, but it really is about English: If you have a BlackBerry handheld device, and you purchase another one (don’t ask me why — you’re the one who bought it), what do you have now? Two BlackBerries, or two BlackBerrys?
Many precedents exist that make the latter seem the obvious choice. In the world of entertainment, some names of achievement awards are nicknamed with the same plural ending: the Grammys, the Tonys, the Emmys. (“The Razzies” is an unfortunate exception; on behalf of the Dailys, I nominate the sponsors of those awards for a statuette featuring an ax embedded in a computer monitor).
And when referring to other brand names based on, or resembling, common nouns with irregular plural forms, this sensible approach applies: Plurals for the names of the car models Camry and Leaf are not Camries and Leaves, but Camrys and Leafs.
Beyond that, however, is the time-honored convention to follow the default setting for pluralizing words in general: adding -s or -es. This is true for the following categories as well:
Names of Nations and Nationalities
Refer to “the two Germanys,” for example, or “the Greeces of the modern and classical eras”). Words for nationalities that end in -i get an -s (Afghanis, Israelis). Note that although The Chicago Manual of Style recommends this style for American Indian tribal names (Hopis), Merriam-Webster’s Collegiate Dictionary lists both a plural form identical to the singular form for this tribe and others with names ending in vowels (Hopi, Cherokee) and the -s plural form (Hopis, Cherokees). If you’re writing for publication, to be on the safe side, use -s; if you’re self-publishing, it’s up to you.
Write, for example, “three Billys in the same classroom.” Surnames are more complicated, however: The default for names ending in consonants and vowels is the same — more than one Smith is Smiths, more than one Corleone is Corleones, and so on — but names ending in -es or -ez (for example, Jones and Chavez) get an extra -es tacked on: Joneses and Chavezes.
An italicized proper noun, like the title of a periodical, book, or movie, should have a nonitalicized s appended, as in “three consecutive Washington Posts,” “a stack of Catcher in the Ryes,” and “all three Mission Impossibles,” though it looks less awkward to relax the reference: “three consecutive issues of the Washington Post,” “a stack of copies of Catcher in the Rye,” or “all three movies in the Mission Impossible franchise.”
Nicknamed geographical terms defy this convention, as when the Rocky Mountains are referred to as the Rockies and the Great Smoky Mountains are called the Great Smokies.
The plural forms of names ending in unpronounced -s or -x are identical to the singular form: “The era between the third and seventh Louis,” “The two Lacroix could not have been any different,” though “. . . Louis III and Louis VII” and “The two Lacroix brothers . . .” would be better.