Anyone else used to stutter like th..th..th…is, then at some point, only blocks?

Anyone else used to stutter like th..th..th…is, then at some point, only blocks? I’m 33M When I was a kid I remember I used to stutter like this “sh.. sh… shai” (it’s a name) Now I only have blocks. Can’t remember when it switched, but it’s been a long time so I can’t even remember.