[Timpy]

>That does not mean that people are free to redefine words as they choose and change their meanings entirely. That is how you get a dialect and then a different language.

There's nothing wrong with new dialects and new languages.

>With emoji, there is no shared understanding precisely because there are simply too many

A lot of people are already using emojis where everybody in the stream of communication shares understanding. Using an obscure emoji is possible just like using an obscure word is possible.

>often with no meaning and when meaning does exist, it is either vague or dependent on culture.

Using text for communication has the exact same feature. Words can be vague or can dependent on culture. Words can have two meanings. Words can be sarcastic or patronizing just like a thumbs up or smiling emoji can be.

By your reasoning, we should ask British people to stop using X's and O's at the end of their texts to indicate the tone of the message. And Japanese people should stop using ASCII emojis that border on artwork to indicate emotion.