In continuation with such Govinda Govindaa analysis, I really wanted to know and talk about why we say 'enakku kaadhu kuthaadha!!'
This could be a possible explanation for kaadhu kuthal. The hearing hole in the ear (natural) is supposed to hear all good stuff (nalladhe kael). Things like rumour, lie and anything irrelevant(not good), when heard, are supposed to go close to the ear but they have to be ignored. So, they are thought to go through only the hole made on the ear lobe (man made hole) and not the hearing hole.
So, when somebody lies, we say ' enakku kadhu kuthiyaachu' to mean that I have my ear already pricked to let off the things like what you say. You don't have to lie and that will only go through my earpricked hole.
This may / may not be right. But this is what I heard. Okay..okay.. I will stop with this.. no such analysis hereafter :)-