When my grandson was coming up for 2, I started to have concerns about his development and autism sprang to mind for me. He was saying a few words but within a matter of weeks he had forgotten those words. He was obsessed with certain things, for example, most little boys with a toy car would run it along the floor but my grandson would sit for ages holding the car in his hand and spinning the wheels with his other hand. He saw the GP who arranged for a hearing test. When that came back as normal she set the wheels in motion with the specialist healthcare professionals such as pediatricians, speech therapists etc to observe my grandson at home and in their clinics. He was diagnosed with autism a few months after his 2nd birthday. As regards your GD, you may be right having concerns. By 2 there is usually the rudiments of speech but if she has a hearing problem, that could be the reason why she isn't speaking. It is the lack of interaction that can be a classic sign of autism. As this is your son & DIL's first child, they probably think her development is normal. On the other hand they may be wondering to themselves if anything is wrong. If she is autistic, it won't go away. It will become more apparent as time goes on. Once she starts at toddler groups, nurseries and generally mixing with others around her age, her parents will start to compare her development to them. I had a very good relationship with my DIL and she asked me if I had noticed anything with my grandson, so I was able to discuss it with her. However, you don't appear to have that type of relationship with your DIL. Tread carefully, because no parent wants to think anything is amiss with their child. It may not be autism but if it is then the earlier it is diagnosed the better. I will tell you now. Her parents will have to fight her corner. Finances and cut backs mean that educational statements are not as straightforward to get as they were. These statements are legal and binding and set out the provision, tailored to that child's education. It opens doors and is worth fighting for. I hope all turns out well for your GD. and your family whatever the future holds.