My daughter says many words and communicates ok around her father and I. But, she is literally mute/shy around others even her grandparents. I have always worked from home since she has been born so she has never needed a babysitter or daycare and literally is never around any children (only child). My parents visit every other week for about 1hr and she says nothing.. as soon as they leave she is her comfortable chatty self. She will talk with them a little on face time but in person they might as well be strangers. She is supper clingy...almost frozen... Doesnt smile just has a blank stare. Is this typical 18month old behavior? Is it because she is never around others? Should I bring this up to her ped?