my daughter is 3 and a half and was referred to speech therapy ages ago. i became concerned when she was about 2 and a half but i told everyone that she understood everything, however the last few weeks i've realised her understanding proabbly isnt as good as it should be - i have asked her questions and she doesnt answer appropriately, and its not because of her speech, she just doesnt seem to understand what you are asking her.
Also really struggling to teach her road safety, she took ages to potty train just started a few months ago, doesnt understand colours, numbers, counting or shapes, has awful tantrums over the slightest things,
i have also just realised that autistic children may line their toys up, and she always does this with her dolls, her picture cards, her bricks etc and hates them being moved out of position, she also points out wheels on her cars, i have read that autsistic children may be more interested in parts of toys than the toys themselves, she also has a fascination with trains and i thought lots of children do but apparently that is a charachetristic as well.
However, although she is only just starting to be okay with other people coming round and still hides away or screams to start with, she does interact with other people quite a lot sometimes and does seem to know what a smile means etc