How much semantic variation is there person-to-person?

I am railing against the paucity of vocabulary for describing mental states and how it has left us, we who wish to analyze language, with a complete lack of information about how diverse the use is of -say- native English. The problem is that most folks don't know proto semantic notation so they have little hope of capturing specific meanings (absent their representation by words and phrases, i.e. syntax-N-grammar) let alone person-to-person variation. So here is the experiment I would want to do. There is a PhD thesis here:
As much as possible ask 10 or so people for a short description of the same thing that they experienced (a ride on the subway, or a trip to buy groceries, or etc.) The questions to answer are:

• Do different people use different concepts to describe the same things? How much variety is there?
• Do different people use the different phrases to describe the same concepts?
• Do different people use the same phrases to describe different concepts?

The approach is to take a short paragraph from each person. Transcribe the paragraph into proto semantic notation and transcribe it into traditional S-n-G notation. The answer to the questions come from quantifying the comparison of these pieces of notation, person-to-person.

We could call this a profiling of language personality. It is an intrinsically interesting topic - the empirical classification of people by their language use parameters. You could have someone with broad vocabulary saying nothing but a few routine things and someone with a limited vocabulary using a broad variety of concepts and saying a good deal. You could have bell shaped curves. The point is that these interesting things cannot be studied with S-n-G notation alone but they can be studied with that plus proto semantic notation.

Like any other form of profiling, doing it for language personality would be a basis for discrimination. Is it OK to discriminate based on language personality? Clearly not, because your references are always based on some other discrimination. But analyzing differences is not the same as basing discrimination on them.