As always, I’d like to make the comment that if something cannot be described it is not relevant to be described.

It’s impossible to tell whether you see the same qualia I do when I see the color blue. However, it would only be relevant to know that if for some reason I had to know it. If there was an application for that knowledge then there would be a testable way to prove it right or wrong. In which case, there’d be a way for me to know it because either I get it right or get it wrong.

Secondly, if there is any measurable/testable property to be known, then it can be described.

The most fundamental form of “measurement” or description is simply difference. If you experience anything, if there exists some thing as part of existence, then it must in some way be different than something else which also exists. Otherwise they’d be the same thing.

Can you understand the term “difference” ? Can you create names/words/references to things? Congratulations you can describe everything that can possibly exist.

(You can construct the words/ideas of sameness, properties, classes, etc. from the idea of difference which makes language much easier and less verbose than using only the word “difference” over and over and over again lol)