I have a grandson who only communicated with immediate family until he was in the 8'th or 9'th grade.My daughter would get soooo frustrated because some of his teachers complained about him not talking in school.He did,however,have one very good teacher,who took her teaching skills seriously,and dug,and looked to find out what could be wrong. It was determined he had a problem called self-mutism,where the children are terrified to speak or do anything around people they dont know well.He would whisper to his classmates to tell the teachers things but he would not talk out loud at school.He was always our very intelligent boy around the family,but would not ,,well he could not communicate with others,It was just terrifying to him. I thank God almight,He is a strapping boy of 15 now,and seldom sees a stranger and he talks to almost everyone.Just a suggestion.This is,i think ,a relatively new disorder that not a lot is known about.You can look up information.WWW.SELF-MUTISM.COM. I hope the little one does well!