Frog in the throat
I have heard that this is an old English saying. Parisians still use their throat to make the R sound. And as you may know, the French are often given the slang name of Frogs.
England had several French monarchs and was occupied by the French. I have always heard that when an Englishman had a sore throat, they would say they had a 'frog' or a Frenchman, in their throat.