Rumor has it soup vendors in commercial areas would use different sized frogs to signify what soups were being offered that day.

Finely carved in a limited amount by families near Chang-Mai, they have a wonderful ribbbbitt like sound when the accompanying stick is smoothly rubbed over the ridges on the top of the frog.  Finish the stroke with a quick tap on the top of the nose to produce a "ribbbbb-itt" like sound.