I agree with the others, don't feel badly about yourself that he isn't picking up his alphabet etc. Every kid does learn at a different rate. My difficult child is now 14, and he has no learning disabilities at all. He did not read until the summer between grade 2-3. My daughter picked up a bit before kindergarten but had most of it down pat by the end of her Kindergarten year. See, everyone is different. My difficult child is now the most avid reader. His reading level tests this year at end of grade 8 showed he is reading at a post-secondary level (university level). So he took longer to get it, but he is now far beyond the reading abilities of his peers.
Simple tactics, if he asks for an apple, say sure! Let's get the apple ... do you know apple stars with A? Make the A sound when saying apple. Next time he asks for an apple, say sure, do you remember what apple starts with? Remind him if needed, A. Ask if he remembers what a sounds like, using the word apple as a example. Little things like that kick in over time. It also helps avoid frustration which can lead to resistance if it feels like a chore or he feels he should know something and he can't figure it out yet. Praise him each time he pronounces the A sound properly or whatever. If he cant' remember, just remind him, get him to repeat, again a "way to go, you remembered A".
Good luck, don't beat yourself up! He'll get it!