One girl actually got + marks for writing an english essay in text speak.
Now as much as I hate txt spk, English used to look like this;
Hwæt! We Gardena in geardagum,
þeodcyninga, þrym gefrunon,
hu ða æþelingas ellen fremedon.
Oft Scyld Scefing sceaþena þreatum,
monegum mægþum, meodosetla ofteah,
egsode eorlas. Syððan ærest wearð
feasceaft funden, he þæs frofre gebad,
weox under wolcnum, weorðmyndum þah,
oðþæt him æghwylc þara ymbsittendra
ofer hronrade hyran scolde,
gomban gyldan. þæt wæs god cyning!
ðæm eafera wæs æfter cenned,
geong in geardum, þone god sende
folce to frofre; fyrenðearfe ongeat
And it's only different now because it got changed and people didn't 'correct' it over time
Shakespeare was written in near-unrecognisable English, at a time when there was no standardisation for spelling. He even spelt his name several different ways in the same manuscripts. I'm sure people wouldn't mark him down for it.
I don't like txt spk, but if it ends up the norm, it won't be any different to what has gone before.