Morbidstorm's answer struck the right chords with me. I think that children can learn so much through games and simple every day activities without even realising.
I've worked with a lot of children and, while there are no real expectations of them in the early years, it does seem to help if they know the basics like colours, numbers, simple letter sounds & recognition. It's not a problem by any means if they don't know these things, but I'd say carry on as you are with games and so on, you won't go far wrong.
Have a look here
http://www.underfives.co.uk/elg.html
This is for 3 to 5s, which is a little older than you asked for, but gives you an idea of what they're working towards.