“Wrongful” use of language - is there such a thing?
Specifically, I’m asking this from an etymological point of view - i.e. how words’ meanings transform over time.
What about “bad grammar”? Is some grammar always and inherently wrong?
Yes, this exists. WHy can’t people call happy gay still and not use it as homosexual? It really pisses me off! Should I learn everybody’s private language?
Haha, get with the times objet petit a! Gay means homosexual now.
Some languages have official bodies asserting correct usage (the Académie française, for instance), others like English not. You can talk of correct or incorrect according to a dialect/time, of course - Shakespeare never wrote “she done gone killed a man”, which would be correct for some Southern US dialects. The same applies for grammar.
Of course, inconsistent use of words or grammar is incorrect. If I Anglicise my spelling and then throw in an Americanization, it’s clear enough what I’m saying, but it may jar a bit. That’s possibly more a stylistic delicacy than an assault on the laws of grammar - ain’t no thing, blood. Grammar, even in ‘lower’ social dialects, or creole languages, is consistent and carries information. For example:
en.wikipedia.org/wiki/African_Am … and_aspect
However, language is used wrongfully all the time. Obfuscation, misdirection, lying and cheating, for example. But as it’s often used, it’s more a statement of social superiority by aspirational educated classes.
Haha, it’s only meant homosexual for forty or so years, please forgive the young upstarts in the anglophone world.
No not really, only if you are talking a different “language” then it pays to be clear at least for the sake of argument.
It also means bad but only in a non homosexual sense. That’s kinda gay but not gay if you see what I mean. 
“she done gone killed a man”
Makes perfect sense to me, but then I do try and get out more.
I think language evolves, if you can’t learn to adapt then you should probably stick with the dictionary and not try and be dynamic along with it. English is evolving fast and loose, as it should.
Many have brought up the difference of dialect.
I’m not going to bother with that; as dialect is self contained and not an attempt to articulate other than what it is presenting.
The difference is that it presents in a different pattern and form than is otherwise the wider common.
However, there is definitely wrongful use of language daily.
A great example is simply this word:
irregardlessness.
Now, I used this word recently in the literal, and because so many people misuse this (unofficial) word, I had to go back and redo the entire original post to make my point clear.
When used to mean, “regardless”; this isn’t a word that belongs to any other category that simply, “wrong”.
ir - regard - less - ness
I’m sorry, but that’s just plain wrong if what you meant was, “regardless”.
ir- not
regard - to take note
less - without
ness - state of
So this means: the state of being without not taking note of something.
Or…regarding.
Where as my intended use of the bullshit word was literally that; to grasp a condition of regarding only disregard and disregard even that: ir-regard-less-ness.
But, like I said, because so many use the word to mean the equal of irrelevance for regardless; the mash-up was completely misunderstood.
So there is one clear example of wrongful use of language; by both myself and others.
I know of another which leads to so many crazy things that it boggles the mind. The word is ‘idea’!!
Pff… 
But without kidding: I think this one is about the question whether or not the evolution of language is ‘wrong’ per se. I would have to say no and yes. No in the sense that it is okay for people to do whatever they want and nickname a guy ‘the nose’ because of hs nose or something. By means of these symbols language evolves. However, the one problem we face in every field of research, but not in linguistics, is that we do not know what the thing is we are examining. The beauty of linguistics is that there has, at one point, been one individual who took a pen and paper and said: ‘x means x, because x means x’! Blessed be this man and why mess a great thing up? So, yes, it is wrong to start using your symbols as the original meaning.
And don’t you forget it!
Language is there to communicate. If you haven’t communicated your idea, you’ve used language incorrectly (well, maybe that’s a little strict, I will allow some room for exceptions to that). If you have, then you’ve done well.
Language has more purposes than that as well, but that’s the primary gauge. Grammar and definitions are there to facilitate communication, not to box it in. Many times I’ve created new words out of well-known prefixes, suffixes and roots and have been understood. That’s not an incorrect use of language despite the words I used not being in the dictionary.
You have to understand, language doesn’t EXIST. We made it up. Only ideas can be incorrect. Not words. You can use words incorrectly, but they are under no circumstances innately incorrect.
I think what is important is that people understand what you were driving at, even if the semantics of grammar aren’t clear, you can avoid confusion by just explaining yourself as you have done here.