Hi Phil,
The Five Tones theory or the sound theory in HG is a combination of four areas of studies.The four areas are Chinese medicine, five tones of Chinese music, five elements of Chinese philosophies and Hung Ga body connections and techniques.
As you can see each one of this areas can be pretty complicated by itself. I don't want to take up too much space in this forum trying to explain the Hung Ga sounds or tones theory.
I think it is easier if I can address any specfic question one at a time.
The sounds "wow, dic,yak, but and hok" are for specfic techniques in CLF. In HG we have similar sounds as well. However as a student becomes more advance, we no longer correspond specfic sound for a particular move. In another words, the same movement might have different sounds. Which one to use is depends on the intend of the practitioner at that moment as long as the proper result is obtained.
I hope this brief response is satisfactory and I was able to answer your question. I am more than happy to discuss this topic further.
peace