"my 3yrs 9 months sister has regression in speech,when she first started speaking she made a really good progress she used to say alot of words but then suddenly she stopped and then after a while she said some new words but stopped saying some of the old words.she doesn't form sentences yet either.she hummes the rhythms of some songs quite well. previously , when she used to be angry she used to bang her head and pull her hair and bite but now these symptoms have cooled down tremendously except for the biting.dr. there re also some weird things she does , she eats tiny stones from the loose tiles on the floor and literally bites into our chalky wall , there's 1 more th she is still not potty trained cause whenever u leave her without diapers her fingers are always itching and if she finds a pen or pencil she might hurt herself down there so my mom didnt potty train her and actually ties her pants so she doesnt take them off and hurt herself.She spins and jumps however in a fun playful way, she's really a loving sister , she smiles and laughs and hugs people and quite recently started looking at me whenever i call her name. dr. do u think my sis is normal or do u think she is somehow autistic. help please"