If I'm a wizard and I have Haste cast on me, can I perform the incantation twice as fast? Slow has a similar stipulation that spells with casting time of 1 action take twice as long, and presumably a spell with 1 minute casting would take two minutes.
Logically it seems like spells require a certain set of steps to perform, so being able to perform them twice as fast would speed up the process. Same as if I had to spend X minutes putting on armor or cutting down a tree.
Phantom Steed has a casting time of 1 minute. Would casting it while hasting myself reduce that to 30 seconds?