Neither of those spellings were his preferred spelling. We know there was a real man named Shagsper. Also, A-She-Speaker doesn't sound like a Elizabethan coinage.
Much has been made of Shakespeare's supposed knowledge of European culture and geography. It's clear to me he didn't have any knowledge you couldn't find in books, and in fact he didn't care about the realism of that, or have extensive knowledge.
For example, he has Bohemia have an ocean coast in Winter's Tale.
He was concerned about the story and the poetry, but not cultural realism.
LOL. That’s a good one. I can see you in Senior English with either a young good looking teacher or an old one that knew “everything “ and buying the entire fairy tale of an illiterate glove maker’s son writing poetry and plays about subjects a glove maker’s son would know nothing about. There is no evidence he could read or ever owned or read a book. Prove he could or did and don’t use the sorry excuses for signatures in his will.