The first person to write &quot;should of&quot; and &quot;could of&quot; instead of &quot;should&#x27;ve&quot; and &quot;could&#x27;ve&quot; was certainly incorrect, because they misheard someone&#x27;s speech and wrote it out phonetically in a way that no one had ever done before. At what point does the incorrect usage become so popular that we ignorant fools start teaching &quot;should of&quot; and &quot;could of&quot; as correct English to our kids?