1. The word "to" is often pronounced "teh," the e being the schwa. One of these days I'll analysize exactly which to's becomes teh's, but the native speakers of English always know when to say "teh" and when to say "to." This is not necessarily a mispronunciation, but does sound funny when you're not used to it.
2. The word "just" is overused and ambiguous, and is almost always pronounced "j'st," at least in this part of the country. I'll let you try to figure out the meaning by yourself, but be warned that it can often be eliminated without changing the meaning of the statement that it is used in. In fact, I once heard some Filipinos picking on the Christian song that has the words, "I just want to praise you," because they understood "just" as a diminutive, as if praising God is a lowly thing. Of course, maybe the song is supposed to mean that the only thing that the singer wants to do is to praise God, but I'm sure that wouldn't last long because, pretty soon, the singer would also want to eat, sleep, poop, pee etc. A better rendition might simply be, "I want to praise you."
3. I often hear "um", which I formally thought was only used as a verbal pause in English, used as a substitute for "them." How did "them" become "um"?
4. The word "can" frequently becomes "c'n."
5. Of course, "going to" sometimes becomes "gonna," and "want to" sometimes becomes "wanna," and "got to" becomes either "got teh" or "godda."
6. Another phenomenon is the use of "'im" for "him." I need to listen more closely to see if this is common.
7. A few people say "-in" instead of "-ing," but not everyone is in the habit of dropping their g's, and it's not something that I've ever heard myself do.
Of course, there are probably other differences in pronunciation, and I don't want to talk about grammar.
When I was younger, I used to think it was cool to not talk properly, though fortunately I never know much slang. I did, though, have the unfortunate and confusing experience of being told out of the blue by some snobs that I took a few classes with that I really ought to talk better. I tried not to think too much of it at the time because I thought that if I were to talk better, I would sound uncool and starchy or that other people would simply think that I'm a foreigner. When I read Remotely Controlled by Aric Sigman, though, I began to see that the television has influenced us to think that it's cool to talk and act less educated than we are. Intelligent people in this country used to and often still do practice their pronunciation, spoken grammar, and vocabulary. This book went on to indicate that everyone must at some point decide between exuding coolness or intelligence, and pointed out that you will get much farther in life, such as in a job interview, if you speak, act, and look intelligent rather than cool, because in the real world, people do still judge your intelligence by the way you speak, look, and act (not to mention whether or not you can spell :-( ).
Because of that, I am left to quake and tremble every time I open my mouth. That abominable accent keeps coming out.