100 years ago? Sure, considering I know people from that time who are still alive, so I'm fairly sure I could hold a conversation with them.
Some one of the average age 100 years ago then, I'm sure you don't know any 130 year olds.
Anyway, the point is, you'll see massive differences for each leap back, and eventually get to a point where English doesn't exist any any form, but I'm sure you knew that.
Languages and dialect are always changing, but for good or bad?
I'm scared now. People actually use lawl in their typing because LOL sounds like this when spoken allowed. Knowing that so many people say lol of "lawl" to the point of typing the sound worries me a bit. A bit.
As long as communication is possible it doesn't matter. There really is no such thing as good or bad, it's all cultural.