Missing my point, I’m afraid. The thing is that there isn’t any adjective for “having girth” other than “girthy” (I’m taking your word for that one!) or for (more or less) “having loft” other than “lofty” but length’s close relative “long” is right there as an adjective for “having length.” “Strength” is related in the same way to “strong;” you wouldn’t say “strengthy.”
Language isn’t logic. Certainly English isn’t, anyway.
You need to be careful how you phrase that. Natural languages haven’t always evolved consistently, and English is perhaps one of the worst offenders in terms of structural inconsistency. Among thousands of examples: “invalid” is the opposite of “valid” (and confusingly also refers to a disabled person), but “invaluable” is not the opposite of “valuable” and means “extremely valuable”.
But as you said yourself over here, making an astute point about the emergent intelligence of large language models that I’ve heard before and completely agree with, there is an important sense in which linguistic skills are intimately coupled to reasoning skills. So yes, the specific structures of a language are not “logic” and are sometimes downright illogical, but there’s nevertheless a strong correlation between the ability to use language well and the ability to reason logically:
There is a relationship between language skills and thinking skills. Research has shown that language proficiency is correlated with logical reasoning and academic performance …
… Additionally, there is a positive correlation between language use, linguistic competence, and critical thinking, suggesting that language use enhances linguistic and cognitive abilities. Overall, these findings suggest that language skills and thinking skills are interconnected and influence each other.
Is there a relationship between language skills and thinking skills? | 5 Answers from Research papers (typeset.io)
Not exactly. It means you cannot assign a value to it. Same connotation as “priceless”. It is the opposite of “valuable” in the sense that we can assign a value to valuable things, but not invaluable things.
Of course, scope creep means that people have started using it to mean “extremely valuable” in some cases. But that’s a usage problem, not a structure problem as you implied.
The English language obviously does not have – and never has had – any architectural blueprint for its structure. Usage, which changes over time, and as periodically reflected in dictionaries and grammar guides, defines the only rudiments of structure that this sorry mess has ever had – yet a sorry mess that is surprisingly functional and capable of beautiful expression. “Scope creep” is how language evolves, or devolves, for better or worse.
I won’t quibble too much with your analysis of the etymology of “invaluable”, which makes sense, but it does seem very much like splitting hairs given its currently understood meaning. Oxford Languages defines it as “extremely useful; indispensable” and Cambridge just as “extremely useful”. And tomorrow I may have to bone a chicken, which definitely does not mean that I’ll be inserting bones into it!
Certainly, but in this case the “in-” actually does mean “not”, and the original meaning is not so different from the modern one, since “extremely valuable” and “of such importance that it cannot be assigned a value” do have a great deal of overlap (especially since you usually can assign a value to pretty much anything).
If you had used inflammable as an example, I’d have no quibble 
. That was just a case of stealing a French word where the “in-” worked more like “en-” (engulf, envelop, etc.).
True. Perhaps it would be better to say that language isnt simple logic.
This, or something like it, really is (I believe) the answer to a lot of the language questions such as ‘if long things are lengthy, why arent wide things widthy?’, but also ‘why do people who live in a different country from me say things in a different way that doesnt make complete sense to me?’
Language is not generally attempting to be logically consistent in those ways. Well, English isnt.
Taking the above as a given …
Does that suggest that people whose native language is highly logical will have a leg up over people whose native language is highly illogical when it comes to their own thinking skills?
Does the inconsistent muddled thicket of English spelling and grammar and usage encourage, discourage, or have no effect on inconsistent muddled thinking in Joe or Jane Average?
I’ll go out on a limb here and speculate “no effect”. While we like to make fun of how inconsistent and “illogical” the English language can be with regard to things like the rules of spelling and word formation, that’s irrelevant in the big picture. The big picture is that any well-developed human language is necessarily grounded in a well-developed logical framework, a rich panoply of logical structures that we always use even if we’re not explicitly aware of them. This is how we’re able to communicate complex ideas, and, according to the aforementioned hypothesis, apparently how we’re able to think of them in the first place.
I suspect that much (if not all) of the research supporting the causal link between linguistic competence and cognitive abilities used the English language as a basis. I also suspect that most of the training that LLMs received, and which led to their developing emergent reasoning skills, was conducted using English-language materials.
It’s used in electronic circuits also, where the output of a circuit stage can be used to change the impedance of the input
I might speculate that it has some influence on the arts. English is a mess, but that does create a sort of freedom that lends itself to, for example, poetry. You can call a morning ‘crunchy’ or a building ‘angry’ and nobody will really bat an eye - the norm, rather than reacting that this makes no sense, it is to try to find the sense.