A.R.
First off, I would investigate medical causes for speech delay. These physical things come to mind at the moment: hearing and ear canal shape/structure, etc., and adenoids.
I know of a little girls whose adenoids were so large that it obstructed her speech and may have even been uncomfortable to talk around! Get a second opinion if possible with an ENT (Ear/Nose/Throat Dr) too.
I'm betting it is an adenoid issue since he can pronounce B's and P's more easily.
Another thing you can do at home is to help him learn to sign. Some will argue that this will delay him even further and cause him to not want to verbalize, but you are actually making connections in his brain that will last until he is READY or ABLE to speak it aloud.
By teaching him a way to communicate you will be easing frustrations too, which in turn puts less pressure on him and speaking may flow more if he is more comfortable with the fact that you can now understand what he needs/wants. A few basic signs are not hard to learn AND has an added benefit that it will be useful as a second language later in life anyway!!
A good resource for sign (as in "American Sign Language" and NOT "Baby Sign") is http://signingtime.com/ They have amazing videos that are entertaining and both of your children will enjoy. Also, they have a show now that comes on public tv now as well that you can tape yourself if you want to try it for free. I'm sorry I don't know the time or station, but I can get that for you if needed (just email me.) They may also have copies at your library. Some of the other brands of signing tapes can be REEAAALLLY boring though!
There are also children's books and adult books at the library with signs.
Don't be afraid of the speech therapist either- he or she will not judge you. It's like anything else too- find one you are comfortable with. They should be able to provide you with resources like websites, books, diagrams of how he should be making mouth shapes to speak certain sounds, etc.
Some other ideas- search for speech-based websites (I have a list I will dig for) and support groups, both online and in real life.
Another thing- I'm new to IL, but in some states the Dept of Education and or state funding is provided and is a STATE LAW that therapy be provided at age 2 or 3 (depends on state) and they may even send someone to your home!
(Call the local elementary school or district for information on this.)
Also, as far as 1 hour/1 time weekly, I would try for one half hour TWICE weekly. It is the frequency and repetition that is going to count for him, AND with him being so young, it will be a stretch for 1 hour of attention at this age.
Feel free to contact me if you would like to chat. I'm not a therapist, but hope to be someday soon! I do sign some if you need to learn some basics.
I will post the websites here when I can dig them out.
-Amanda
(____@____.com)