100 mph by me babey.
I am not quite sure who the fastest pitcher in general would be, but a few pitchers such as Trey Quinn, Kennon Fontenot, and Kyle Carter are known for pitching in the low 80's. The fastest little league pitch I have ever seen was 84mph by Kyle Carter from Columbus, GA.
I don't know exactly but I've watched the Little League World Series enough and they always refer to Little Leaguers pitching speed in relation to MLB and I believe that 70 mph Little League would be around 100 mph MLB A 70 mph little league pitch is equivalent to about a 111 mph MLB pitch. (This is calculated based on an average little league pitch at 57.5 mph and an average MLB pitch at 91 mph.)
There is no official fastest softball pitch recorded. The NPF (National Pro Fastpitch league) claims that pitches of 70+ MPH are common. The fastest pitch recorded at the 1996 Olympic Games was 73.2 MPH.
82 mph from some kid in the little league world series
Minor Leaguer Steve Dalkowski threw a 108 MPH pitch, the record. The fastest pitch recorded in a major league game under modern valid conditions was 105 MPH by Aroldis Chapman.
You must pitch the ball in 12 seconds in pro and little baseball. If the batter doesn't come, then you just have to pitch it.