Here is how Those Young People are wrecking English today: They are reinterpreting the period (the "full stop" in Britlish) as a mark of passive-aggressive hostility.
At The New Republic, Ben Crair writes that in "text messages and online chats ... people use the period not simply to conclude a sentence, but to announce 'I am not happy about the sentence I just concluded.' "
This seems to be a thing.*
And at Language Log, Mark Liberman is hugely amused that this article has drawn scores of comments, including many "displays of entertainingly clueless bile." You who have heard from the peeververein before will recognize the specimens Professor Liberman cites:
No. This is not even remotely true. At least, it shouldn't be. People should spelled properly, punctuate properly, use proper grammar, no matter the medium. Not to mention that people should say what they mean, and mean what they say.
A period does not indicate tone or emphasis. A period indicates the end of a sentence.
This below is the proper way to use punctuation, as well as the proper way to express oneself:
Ben Crair, you are an idiot.
Just as baying peevers appear unable to grasp the concept of register, they also have difficulty with what eighteenth-century writers would have understood as decorum, that different standards and conventions apply in different circumstances and contexts.
Those text messages, typically all lowercase, with slangy abbreviations and acronyms and (Great Fowler's ghost!) emoticons, are meant to operate in a way that is distinct from standard formal writing.
Look at it this way. You could wear a dinner jacket to a barbecue; it's a free country. But you would look out of place and would likely feel out of place. Similarly, you would look out of place if, in a pathetic attempt to be With It, you used textese in a formal context.
Conventions, like manners, word meanings, and grammar, exist because people adopt them, and they are mutable. It once was conventional to close a letter with "Yr. most humble & obt. servant," but it would be silly to use that seriously today. The people who write in textese have started to see periods as expressing unvoiced irritation or anger; you can flout the convention as you choose, but you ought to recognize that it may be there.
For my part, of course, I will continue to use standard capitalization, orthography and punctuation in text messages and tweets. It will look antediluvian to some, who will brand me a fogy. And since every sentence will end with a period, they may think that I am perpetually angry (not far off the mark).
I like to think, though, that some will shake their heads and say. "oh yeah, mcintyre, he's old school"
*Perhaps not so novel a phenomenon. From Isaac Babel: "No steel can pierce the human heart so chillingly as a period at the right moment."