I think Shakespeare wrote quickly with a quill and ink and parchment. His copiers must have possessed considerable penmanship skills as well. I think he wrote as he vocally created, playing all the parts while writing, making the sense of every word and line clear with sound.
So if you know a speech REALLY well; you can create a different pathway through it, just by starting differently or letting the text create different thoughts within you. Thoughts within the director’s vision might be best. Thinking fresh thoughts may colour text differently, pace it differently, clarify it, hopefully. It is called play and welcomed by other actors who seek listening and thinking in real time. They also love to play with other actors they respect. Anyway, hearing one’s voice, hearing the invented words affects the speaker as well as the listener. They are new to him as well. Just the pure sound of extreme emotions, or deep thoughts can be highly affecting and revealing. I often learn from my own voice. Shakespeare’s characters, with such words, can’t help but learn from their own inventions.
I imagine Will writing early in the morning very quickly, thinking, “I can’t believe the shit I am coming up with tonight!” Ben Jonson claimed he never blotted a line, so he very well could have penned ‘to be or not to be’ in twenty minutes. Surely, he felt wonder at himself, heard it through his own creations, through the sounds he was voicing. He must have experienced wonder at himself!