Toddler's development

My son just turned two. Is it normal that he doesn't speak any simple sentences yet? He knows tons and tons of words, he knows the alphabet, he knows his colors, shapes, and even numbers 1-10 (and almost 11-20) but he doesn't really speak even two-word sentences yet. I worry that could be because I hardly get him out of the house and around other people, especially other kids (long story short, we've been down to one car for AGES because the other car is being used by a family member). We should be receiving a leased car soon, but now I'm paranoid that his social skills have already been wrecked. :( I live in Ohio so it's freezing outside now, so no park before hubby works, and we don't really have any kids his age in the neighborhood, so I kinda rely on leaving the home to get him around other kids. I don't really have close mommy friends right now. Sorry about the long post, but what do you think?