What is the difference between TDNN and CNN? I read about time delay neural network (TDNN) and I am not sure I understood it. From what I read it seems that tdnn works just like  one dimensional convolutional neural network (CNN).
What are the differences between the architectures, if they exist?
They are the same, as far as i can see. The name convolution usually applies to spatial not time dimensions, but that is only convention. Wikipedia also links the two.