People throughout history have complained that thing A or reason B will kill a thing, but what they're really complaining about isn't the killing of the thing but the changing of the thing, and all you have to do is look at the hundreds of languages that die out because they couldn't change and adapt to know that change isn't what kills the thing.
A number of years ago there was a big antitrust lawsuit against a company that made slide rules because they had a monopoly on the market. They failed to adapt to changing times and now nobody even remembers the company.
The fact that English changes doesn't mean it's about to die. Currently we have a cell phone sub dialect evolving, and if it's strong enough and popular enough then maybe some of the words will end up in a dictionary. Not every word will - remember, language is a big popularity contest, and not every word will win. Thomas Edison wanted everyone to say, "Ahoy!" When they answered the telephone, but "hello" became more popular and thus became a word... before 1840 or so it didn't exist.
Chaucer, considered one of the greats, was a crappy speller and punctuator... partly because before him there was no concept that a word had to be spelled one specific way. He was the one who solidified the spelling of lots of words because people started spelling things the way he did... and he didn't even use consistent spelling.
Anyway, if English dies because of texting, we can always learn Chinese.
