I can't comment about Speakmans Kempo. what i can say is that there are many different martial arts that use the term Kempo or Kenpo to describe them. Like Karate styles they can be similar of very different from each other. The style of Kempo i studied came from China to Korea, to Japan, before coming to the U.S.A. we are different from any other kempo or kenpo style that is commonly known. All kenpo or kempo systems have joint locks, chokes, take downs, throws, ...etc.
I mention that my style is different to make it clear that my Kempo does not look like Parker Kenpo, Ko Sho Ryu, Tracey's, or Okinawan Kempo, ...etc. The style I study has no roots in common with any of those styles.