Many ablaut forms are no longer as obvious as sit and sat . Hood and hat , for instance, are ablaut forms. Mike's crutches enter this picture once again as crutch is an ablaut form of crotch which was originally a form of crook . For instance, a dribble is a continuous drip . Jiggle and joggle are repetitive jigs and jogs .
Chatter is continual chat .
Well, perhaps that last doesn't quite make sense but etymologically that is what a shovel is - something to shove with. Mike's car was a little crumpled in the accident, too. Crump is also an ablaut form of crimp and cramp . I haven't gotten very far except to find that it may have come from China. Sure, we can give you a hand with this one.