Is it reasonable to say: "This is going to be the most amazing day by so far!" ? I mean the "by so far" part. English is not my first language, but I caught myself typing so and started wondering where did I get that from. It's just without the "by" I feel like something is missing.
Learn English – Is it reasonable to use “by so far”
grammaticality
Related Solutions
We are most likely "doomed" in that these changes are more or less inevitable. But we are not "doomed" in the sense that the language is actually breaking or somehow falling apart. Languages have been around for thousands of years, evolving and changing; no language has ever evolved itself into a corner or created a construction that makes the language non-functional.
Many of the "correct" English words and constructions that we use today got their start as stupid-sounding "mistakes". Our case and gender systems have almost vanished completely, for example.
In fact, if I am not mistaken, a couple hundred years ago, "the only people who passed the test were Anna and I" would have been the pedantically correct version, and "Anna and me" would have been the sloppy "wrong" version; it used to be that the copula would have nominative case on both sides (e.g. "it is I", not "it is me"). Maybe that puts things into perspective a bit.
If you find certain things silly, there is nothing wrong with feeling that way and avoiding them — and not all variations become mainstream. But, it is pointless to try to make any significant effort to stop these changes. Mainly because it is inevitable, but also because you'd only be protecting a momentary instance of a thing that is constantly in flux.
(Edit: I should also add that I don't even necessarily agree with you in the case of lay and lie. Most people don't even know the correct paradigm for conjugating these verbs. I interpret the changes in popular usage to mean that these verbs are undergoing regularization; the old paradigm seems to be inherently confusing and I welcome the change: the language is fixing itself. I thought this might also be an interesting point of view to consider.)
Addendum based on the question's first edit: I recommend reading up on Standard Arabic to consider attempts to stop language change in its tracks. Because Muslims believe that the Arabic used in the Quran is holy, they have attempted to maintain this version of Arabic. This Standard Arabic is the only "official" Arabic, it is the only one they learn in schools, and it is the only one they write in. But, in day-to-day use, you can't stop language change. Instead, every region has evolved a distinct dialect (and these "dialects" really stretch the definition of that word to its breaking point). In many cases, they are not mutually intelligible (for example, Moroccan Arabic and Baghdad Arabic), and nobody in the Middle East actually speaks Standard Arabic as a first language. Most people have an imperfect command of it anyway except for the most highly educated. Most of the time, if speakers of different dialects want to communicate, they speak in a simplified hybrid of their own dialects and Standard Arabic (leaving off things like case marking that exists in SA). The Standard form has become different enough from their spoken language that they can't actually manage to follow the rules automatically.
This also means that if I want to learn useful Arabic, I have to learn Standard Arabic to read and for some TV programs, and I have to learn another language in order to actually communicate with the people around me. There is not much practical benefit to this system (but they aren't doing it for practical reasons).
If for some reason we decide to freeze English as it is now and make a concerted effort to maintain this form as it is, we will inevitably end up with the same messy diglossia situation that they experience now in the Middle East.
Addendum after second edit: I can't keep up with this moving target :)
The phrase "I can't hardly wait" is incorrect.
I suspect it is the result of a confusion between:
I can't wait
and
I can hardly wait
which are both correct.
The phrase
I can't hardly wait
doesn't make sense: it would mean "I don't find it hard to wait", which is probably not what is meant.
Probably adding to the confusion is the 1998 teen movie "Can't Hardly Wait". It is possible that the title itself was picked up because the expression is in vogue in American high schools although I did not find any confirmation for this hypothesis.
Best Answer
No. You're conflating two idioms with far:
By far modifies comparatives and superlatives, and indicates that the degree to which they exceed other compared things is very, very great. This is the best one by far.
So far is a distance measurement meaning as far as this. It's often used with the TIME is DISTANCE metaphor theme to mean up until now. This is the best one so far.
Since this is a superlative expression, you can use by far; since it means up until now, you could also use so far. Either one works.
But you can't use them together. Pick one.