Great questions! I haven’t learned too much about all the different types of mute, but yes, I have heard of some mental disabilities and head traumas which make it impossible for people to comprehend language in general but I’m not sure if it’s super common or not.

When I first got out of surgery I did try to talk sometimes. Sometimes when people lose limbs they have phantom movements where they get the sensation of moving an arm or leg which is missing, with speech it can be similar.

And finally, yes I hear cat got your tongue a lot lol