Even though 𐑕 and 𐑟 follow the rule about voiced and unvoiced letters, you can see that they look a lot like the ordinary letters "s" and "z".

Here is a place where the ordinary spelling tricks you. When there is more than one of something, we usually just write an "s" on the end of the word. So "oat" becomes "oats", and "toe" becomes "toes". But that "s" really stands for two different sounds: a s sound in "oats" and a z sound in "toes". Listen carefully and you'll hear. In the Shavian alphabet, we write these as the sounds they really are.