Spelling, as easy as A-B-C?

Why do these homophones have such widley diffeernt spellings?

Which and Witch.

I don't often see them confused.

But I got a message recently, which spelled peak like peek. That's a common mistake. One which the spell check will not detect.

There was this thing called a dictionary and it gives proper spelling as well as usage for the word. I whish more peple used them.