There is an aspect of this thread that strikes me very forcibly. It is an important point in my opinion. I shall attempt to summarise ("summarize") it as clearly and as fairly as I can. Many of the complaints put forward about "bad grammar" are in fact moans about speech patterns and usages which are in fact dialect or regional variants. English has dialects. Some of these have achieved scholarly status - US Standard English, British Standard English, etc. Others are more casual and informal, but I would hesitant to label them "wrong" in every situation. "I did not know where Jim was at" might be inappropriate in a piece of formal prose but perfectly fine in relaxed conversation in certain zones of the English speaking world. We all have our pet hates (I particularly dislike misuses of 'of' e.g. "I would of gone sooner" which are common in Bristol, England, where I live -- even worse, "I would of gone sooner if I had of known it was that big of a deal"*) but a language scholar would merely note them as dialect variants. They can bring colour ("color") and life to speech and without them we would all talk like books.
* The first 'of' replaces the standard 'have', and the second and third are nonstandard insertions.
