Are you referring to french? Because, if anything, french in France has an insane quantity of slangs and has an extremely emergent vocabulary. Much more so than any English speaking country I can think of. Quebec isn't really influenced by the Académie française yet has a much more "correct" usage of the language generally speaking.
Maybe it's a totally different language but still it goes to show that even a very prestigious central authority doesn't make a language better or less prone to diverge. Regardless of the reason, French is evolving much more quickly than English.