I don't offer a formal program. I am rabidly against pre-K or forcing a child into formal learning before the age of 6. I wouldn't even send mine to kindergarten if I had kids. I won't be part of it, but I know that I'll lose all of my kids when they turn 4 because our school district offers full day pre-K. Of course they are going to ditch me for the free child care they get through the school. Of the 4 I have on my roll now, 1 will turn 4 ten days before the start of pre-K.
The others missed the cut off by 7 and 10 days, so I'll have them an extra year (of course, that's assuming I still have them 2 years from now.)
That said, I've been teaching them since they were 6 mo and 10 months old. I never say ball, I say round ball or red doll. I never say blocks, I say one block or two blocks. In a book, I say "That's a dog, woof woof". The oldest knows almost every animal sound. Her cat is priceless.
I am constantly using color or number or shape words, even though I know they aren't ready for them. I think that when their minds are ready, they already have those reference points. They can already bring me the yellow block at 19 and 20 months old. I'm not sure why I do that, it just is a natural thing for me--I think every moment is a teaching moment for a young child. I even did it for my grandkids and for the neighborhood kids that always hung out on my porch.
I have no plans to have a formal program unless they decide to leave them with me instead of going to pre-K.