https://plato.stanford.edu/entries/sortals/

Tell us what you think the underlying issue is. The question as written is ambiguous and vague enough to be uninteresting.

But to start down the rabbit hole of discussions lacking even preliminary definitions, there is no such thing as a something that can be pluralized.

But to start down the rabbit hole of discussions lacking even preliminary definitions, there is no such thing as a something that can be pluralized. — tim wood

I am not sure what the confusion is about 'pluralize'. Merriam Webster online dictionary gives a decent definition: "to make plural or express in the plural form." Thus to pluralize means to add a 's' to the end of the word (in English) making it plural form. The Google search dictionary adds: "cause to become more numerous." Merriam Webster online dictionary definition of plural: "relating to, consisting of, or containing more than one or more than one kind or class."

Thus, there is something that can be pluralized: Words can be given plural form. I don't know of any other somethings that can be pluralized, but words certainly can.

Merriam Webster online dictionary at something: 1a. some indeterminate or unspecified thing. 2. a person or thing of consequence.

Something about having to begin the discussion in this way feels like Bill Clinton's famous answer at deposition: "It depends on the what the meaning of is is."

Wikipedia has an article on Sortal: https://en.wikipedia.org/wiki/Sortal

I am not sure what the confusion is about 'pluralize'. Merriam Webster online dictionary gives a decent definition: "to make plural or express in the plural form." — Necuno

You are aware that the the something that is the word "rabbit" is not the same word as "rabbits," yes? Rabbits is indeed the plural of rabbit, but, we - I - was speaking of a something. If you change it, it's not the same something. Pretty clearly, rabbits is not the same thing as rabbit. Now, how about sheep?

This may be an interesting topic. Stanford.edu has an article on it.
https://plato.stanford.edu/entries/sortals/.
But we're lacking why you think it is.

As to your question, sortalness seems to be a quality - an accident - that can be assigned to something. Perhaps like redness. The flag is red, while of course the flag knows nothing of redness or any other colour (it could be a white flag in a red light, for example).

The question would seem to devolve to, "If I can think about a something in a certain way, can I include that something in the class of things I call sortals (i.e., because they can be thought of in that way), such that if I cannot think of that thing in that way, then I cannot so include it?"

From the Stanford article:
"The three main ideas are that a sortal
1) tells us what the essence of a thing is
2) tells us how to count things of that kind, which requires knowing which things are different and which are the same
3) tells us when something continues to exist, and when it goes out of existence
John Locke, who coined the term in 1690, was primarily concerned with (1), Peter Strawson, who in 1959 was the next to use the term, was primarily concerned with (3). Two historically intermediate philosophers who did not use the term but were interested in the concept, Spinoza and Frege, were primarily interested in (2)."

And this, at first cut, seems all about how terms are defined. "essence," "thing," "count," "knowing," "different and same," "existence and non-existence." Simple, but the devil is very much in the details.

For example, what criteria for determining when two things are the same?