If language changed so much in the past, then why do you think we tend to think of changes in the language today as slang or mistakes?

Because people have it written down now how it should be said and now call it a rule.

Explanation:

When people make a rule they like to stick to stick with it, so if they were to have English say as an example and use the word stick, they would not like for you to say it any other way because its how it says it in the rule book"dictionary"

the answer would be yes because the basket is full.