Educating a child who is severely behind


I am in a relationship with a lady who has a 3 year old son. I’ve grown to love him like he’s my own child.
It’s clear that he’s behind in terms of development due to lack of attention in the first two years of his life, for reasons I don’t completely blame his mother but reasons I don’t feel are appropriate to disclose.
I’m currently focusing on helping his speech and potty training as a priority, with helping in other areas and being a general father figure. I believe my efforts have paid off because I’ve been told his rate of development has been remarkable since I became involved.
I was just wondering if anybody who has a child or has studied this area has any extra ideas for my to try? Are there any techniques or methods I can employ to help his development along further?
I’m asking here because this is hacker news and its going to take a seriously effective and elegant hack to get this kid where he needs to be a d further. I can’t stand to see a clearly intelligent child locked behind a wall of impeded speech and behaviours typical to a 1 year old.
I eventually want to to teach him the wonders of computers and how to tell them what to do. It will be very hard if we can’t communicate effectively.