mompa,
hi, I have two late talkers. I simplified my language with the first and that was enough, he combined words at about 2.8 and then grew out of it completely. My second has required more intensive help (from me). He didn't combine words until 3.1. He is finally catching up (4.8 now).
Your problem is, you don't know which category your child falls into right now. Better to help too much now than regret not helping enough later.
Re the drinks, you owe it to him not to waste time blaming yourself.
Get his hearing checked if you haven't done so already. It could be glue ear.
Assuming it's not hearing, the best thing you can do right now is buy the book "It Takes Two to Talk", published by Hanen, available through Winslow, about £32 but worth ten times more, and work through it religiously. It will show you how to adapt your own behaviour so that you are giving him the best possible opportunities to develop his language. It will show you how to stop saying " say this" and instead create situations where he is motivated to talk.
The reason why I recommend this so highly to you is that it is 100% positive, has no scary milestone charts, no scary syndromes, no blame, no negative stories, no off-the-cuff phrases that will linger in your head when you're trying to sleep at night - nothing frightening at all in fact, just lots and lots of positive techniques. And it is so clearly written that you can read it even when tired. It trains you to use the opportunities that arise in daily life so you don't have to make big changes to your routine either. Ask any speech therapist - they will all be happy for you to use it.
Go ask about speech therapists - you might get put on a waiting list (in which case, all the more reason to start now) or you might see one straight away. The good thing about a speech therapist is that they are trained to figure out what the "block" is (is it hearing? is it understanding? is it finding the word to say back? is it not understanding the etiquette?) and that can help you target your efforts more effectively. But be under no illusion, you will be the one doing most of the work.
The drinks thing is just a distraction from the job you need to be doing right now. Good luck.
PS, this 3.5 thing must surely be a typo or a misunderstanding?