S.S.
You said your child is only 20 months old? How does she get to attend school at such a young age? Just curious.
As far as the other concerns you have go, kids learn by imitating what they see, whether it be t.v., parents, other children, etc. Just remember, when you are doing soemthing in front of her she's probably going to imitate it......so be good!!!
As far as people not speaking, well that's unfortunately the world we live in. This may be a good opportunity to teach your daughter the differences in people. Some speak, some don't, some are friendly, some aren't, etc.
I do know that your husband needs to try and spend as much time as he can with your daughter even if his job does take him away. I know from experience that if he doesn't she may grow to resent him and know that only "mommy" was there....and she probably thinks that now because she seems to be a very, very bright little girl.
Just let her develop her own personality, likes, dislikes, etc. I think that you are doing a fine job of teaching her... Please let me know about the school, where I live they don't have schools for children that young. Thanks!