Worried about my niece

Hi, Im worried about my niece,shes 3 years old. I think shes delayed in speech for her age alot of her words are unclear,she is very high pitched also. When she looks through the argos book she starts to 'hand flap' and makes lound noises. When her mum cuts her finger nails she goes into one badly and after she walks around with her fingers streatched out almost like she feels violated. She hates things that makes loud sounds and doesnt like new toys,if someone buys her a new toy it has to be left for her to explore in her own time. I took a small spinning top round for her to play with and she got that upset by it she made herself sick. She does show eye contact and is very smart in counting and can read alot of words from flash cards although the words arnt always clear.
I am worried about talking to my sister about the things i am seeing in case im wrong or she falls out with me.
Can i have some advice please?

[Jason C Bourret, Ph.D., BCBA-D]

Really, the thing to do is to recommend that the child be assessed.  The hand flapping and deficit in communication are common in children with autism, but typically developing children may have these issues as well.  You obviously have a concern, share it with the child's parent and suggest the parents have her assessed.  Early intervention can make a huge, huge difference, so the sooner action is taken, the better.