Personally, I think the English language constantly 'evolves' over time....
I remember the furore when texting became the norm and many people started using 'text speak' in their everyday communitication. However, over the past few years, with autocorrect and predictive text becoming much more sophisticated, it's actually much harder and more time consuming to type 'text speak' into your phone nowadays.
There will always be those that aren't able to spell as well as others, and emojis will always have an appropriate place in communication, but I don't think we need to worry too much about the decline of the English language...
Or do we?
)