I didn’t get worked up because of your comment that the -es is a third-declension Greek form. I know this, and was purposefully avoiding an etymological discussion, wanting instead to connect the use of the form to the use of Latin phrases in English. I didn’t need the plural endings of thesis etc. to be Latin, because I was putting them in the same group of usage in English. And I tried to gloss over the issue by using “Latinate”, though apparently this was unsatisfactory.
Most English nouns can be transformed from their singular into their plural forms by applying a few simpleand relatively standardized rules, such adding an "s" or "es", or changing a final "y" into "ies". Irregular English nouns are those where the relationship between singular and plural forms of the noun do not follow these standard rules, for example "person" (singular) becomes "people" (plural).
The plural form of essay is essays.
*The jury still seems to be out on whether URL (acronym for Uniform [or Universal] Resource Locator), the address of a Website on the World Wide Web, should be pronounced like the name of your Uncle or as a series of letters: U*R*L. The information technology experts at the college where I work use the "earl" pronunciation, and one would have to ask why you'd want to say "you-are-ell" when a simple "earl" would suffice. In either case, though, the plural of URL would be spelled URLs. by the way, would insist on U.R.L.'s because their style guide requires that everything be capitalized in headlines and URLS would look dumb in a headline. So use URLs unless you're writing for the