What is the plural form of the word “vertex”? Why is it irregular?

Vertices.

Why? Because the word is straight of out Latin, and Latin has a lot of declensions that look weird from the perspective of English.

In particular, the plural vertices suggests that the singular should be vertix, just like the singular of matrices is matrix. There are a lot of –ices plurals corresponding to –ex singulars in Latin thoough, and historical linguists mumble something about analogy and/or vowel reduction. Sihler’s New Comparative Grammar p. 67 is my source for the mumblings.

Why use the Latin vertices rather than a regular vertexes? Because (a) vertex is a learnèd, rare word; (b) vertex is a word straight out of Latin, that never really was assimilated into English; (c) even common Latin words following the –ex -ices pattern don’t readily get regularised into English, precisely because –ex is so redolent of Latin.

We say indexes now, but we still say indices too; it’s the more common meaning of index, as what’s in the back of a book, that gets the English indexes plural.

What interesting differences would there be today if I went back in time to ensure that “-tion” words in English instead ended in “-tio”?

where the endings “-tion” and “-tio” both were in use.

Alack, not so.

The Latin ending is nominative –tio, genitive –tionis,  dative –tioni, accusative –tionem, ablative –tione.

That’s a pain, sure, but the common pattern is that the underlying ending seems to be –tion– (and that’s what you’d reconstruct the proto-Latin nominative as). The nominative drops the final –n since there’s nothing after it, since Latin doesn’t normally have final –n‘s; that’s what makes a lot of Latin declensions look inconsistent (and even more Greek ones). 

When the Latin case system melted down, speakers went with the regularity they could see, and reduced it all to –tione (Italian) or –tion (Old French). English got its Latin from Old French. And it did not have the option of getting them without the final -n, straight from Latin.

Much more recent loans straight from Latin will take them as –tio ; the only one I can think of though is fellatio. And the taboo nature of it probably explains why it wasn’t Francified to *fellation: it was not so much a borrowing, as a way of hiding the meaning, so it wasn’t a real English word.

So…

What would happen if you went back and switched –tion to –tio?

It’s an odd thing in English to have words ending in –o; that’s not an English thing, it’s an Italian and  Spanish thing (see List words ending with io ). It’s an Italian and Spanish thing precisely because it’s not a French thing—French aggressively dropped final vowels (-tione > -tion; *bono > bon). You couldn’t switch tion to –tio in isolation back then; you’d have to make sure all those final vowels were kept in general, because if you didn’t, people would make –tio sound like something more familiar. Like say –ty (which comes from Latin –tia).

To make that work in turn, you’d basically have to have English borrow words from  Italian or Spanish instead of French. Words like braggadocio and machismo would be closer to the norm than the exception. And as an added bonus, English would sound even less Germanic.

Opera singers would be grateful.

Is Greece more West or East?

Greece was an Eastern country in 1832, and has been telling itself ever since that it’s a Western country. (That’s what the Westerners were telling her too. At least, to her face.)

By the 1990s, Greece was a Western country. But the Eastern roots are still there.

When the switchover between East and West happened is hard to answer. I think it’s the 1980s, others might think it was the 1880’s.

There’s been a lot of talk here on Quora about Greeks calling themselves Roman (Ρωμιός). The Hellene/Roman dichotomy is the Western/Eastern dichotomy.

Does Monaco have its own language, or local dialect?

Yup. Close to the dialect of Genoa, which Monaco sits next to: Monégasque dialect.

There’s been some promotion of Monegasque recently, but Monaco isn’t in the right part of the world for promoting small languages. The Duchy of Savoy (in the same general area, and homeland of Franco-Provençal/Arpitan) made French its official language three years before France did, and 300 years before they became part of France.

Are memes a novel linguistic category of proverbs?

Hm. In this subculture, sure. Adage at least, if not proverb.

The fragmentation of culture in the Anglosphere, and the lack of common cultural reference points as a result, is a strange thing. It feels unprecedented. You can’t fall back on common literary references any more. The Anglosphere thinks traditional wisdom is old hat and values innovation; so proverbs are derided as cliches (a big difference from say Greekdom). You can fall back on pop songs and movies to some extent, but only to some extent, because of the fragmentation.

So in this culture, memes fill a function. They are visual, because the communication enables it. Maybe not completely unprecedented; there’s lots of coded memes in Renaissance painting, for example. But yeah, they’re a proverb of the future.