I have a 4 year old and an almost 2 year old... he'll be 2 in February. He's just starting to get the idea that he can talk! He's been saying ma and da for a few months, but really nothing else. I've been working with him more on animal sounds (they're fun and easy to say). His favorite right now is the sheep. Loud and angry sheep... BAAAAAAA! But he laughs so hard when he says it, so we have fun with it.
I wouldn't worry about it if he's communicating in other ways. Does he pull you over to the cupboard when he wants a cracker or cookie or something? Does he point to things when he's excited about it? ...Like he wants you to see it, too?
Have you tried sign language? I started my boys on sign language early... like when they first started to eat rice cereal at 4 or 5 months. Simple things like more and all done, milk, that kind of thing. Now my 21 month old can tell me, no, I want grapes, not crackers... all in sign. That cuts down on frustration sometimes, too.
I will say, however, that it's nice to know that mine isn't the only screamer. Despite the sign language efforts, he still screams if he doesn't get his way or big brother takes a toy, or Thomas the Tank Engine crashes on the video or the wooden railway in his room! So, if you have a cure for the screams, I'll be happy to hear it. ;) I think once he starts talking more, he'll grow out of it, and have other things to say... I hope! ;)
Another thing is to ask your pediatrician at his 2 year check. She/He will be able to tell if there's anything to be concerned about. My ped says some kids just start speaking later. If they're communicating in other ways, not to worry. My brother's two kids didn't start speaking until 3 years old and they're both just fine and doing great in school.
Good luck on the screaming thing... and if he's anything like my older boy, once he starts talking, you'll wish he'd stop at least for a little while each day.! ;)
You know, WOW! I posted my response before I read the others... PLEASE don't get uptight about it. Your son will sense your frustration and that might make things worse. Early Intervention and Child Find are great programs, and certainly check it out if you feel it's necessary, but JEEZ, there's so much gloom and doom in the other posts, don't panic. Evaluate the situation: if he communicates in other ways, if he can follow simple commands, (my little guy just loves to pick up toys. I say time to clean up... can you go get that blue truck and put it in the toy bin? Thanks, buddy! and he makes a game out of it.) If he can do these sorts of things, or even just responds to your voice inflections... happy, upset, etc... does he stop when you say no or stop or whatever you use for that? If so, just keep giving him words to use... "OH, that's the red block, that's a yellow truck, see the blue train?" He'll get it. Don't panic.