You have only to observe how much speech has changed in the last 100 years. I expect if we heard speech from 500 years ago we would struggle to understand it.
And to think how languages have evolved in the last 1000-2000 years! No, we have to accept that speech and language will be forever changing.
"Like" is the new ""er", "um","hmm" or "ah".
I never fail to be amazed how many different languages there are (in Europe alone) and in how few generations these happened. In the last 2000 years there are, perhaps, 80 generations only!