if I'd knowed you was coming I'd of baked a cake

Another time I might deal with the moods (conditional and subjunctive) and the tenses (perfect and pluperfect). Right now I want to consider OF.  I think I've complained before, wondering about "not that  big of a deal" and "it's about the both of you".  Why did OF start appearing in those phrases? "Big deal" is okay and so is "both of you" - no OF necessary. CORRECTION:  I mean THE in both of you - gratuitous and unnecessary.  Ohm, dear. that's careless of me. Ah well.... Then there's bored. You'll hear people saying they're "bored of something".  I'm bored with hearing that.  It should be WITH, not OF.  I think at some time being tired was confused with being bored. You can be tired of something; I don't think you can be bored of something. 

It's never-ending. The price of eternal vigilance is eternal vigilance.