Stockfish 4
What does this mean in plain english?
Attack.
Unprecedence attacks = Attack? I know the word precedence, but there must be a better answer...
Never happened before in history.
I'm assuming he means that the new Stockfish is playing unprecedented attacks, meaning either more or better attacks. It wouldn't be a surprise, as the new Stockfish is stronger, and it's always been an aggressive engine going all the way back to its predecessor Glaurung.
The new release is playing the unprecedence attacks.