Archetypal Statuary

When Archetypal Statuary enters the battlefield,
choose any keyword ability. (A keyword ability is
a game term, such as ''flying'' or ''haste,'' used as shorthand for a longer ability or group of abilities.)
Spells you cast with the chosen keyword ability
cost up to {1} less to cast for each spell and/or
permanent with that keyword ability you cast
this turn and/or you control.