While there might not be anyone fitting exactly that description, there are a few close calls:
-Disciples of Ancient Tomb: they don't interact with the outside world
-Mu Wanqing
-Shi Potian: up to age 12, had never talked to anyone except his "mother" (who was very cruel to him) and his dog. Unfortunately, he didn't know martial arts back then
忽见柳荫下两个小孩子在哀哀痛哭,瞧模样正是武敦儒、武修文兄弟。郭芙大声叫道:「喂,你们在干甚麽?」武 修文回头见是郭芙,哭道:「我们在哭,你不见麽?」