Tenses

Sometimes,  things other people say hurts my ears like nails on a chalk board.

"I seen the spelling in the book." -Unidentified female in class

NO NO NO NO!  You SAW the spelling in the book. I understand that both words represent that the event happened in the past and not the present but there are wrong and right ways.  This is how I would use this verb in the sentence:

I/You/They SEE the spelling in the book.   He/She/It SEES the spelling in the book.

I/You/They/He/She/ SAW the spelling in the book.  

The spelling was SEEN in the book.  (I believe this is a passive tense since no particular person/thing is "seeing").

Should this agitate me?  Is this what English will be developing in to? 

I wonder and hope not.  ... a man became I and that's how.