The other day I was walking home when I was invited into a neighbour's garden for a cup of coffee. The grandmother of the family (translated by her granddaughter who was learning English at school) said that she couldn't speak English. To speak English, she said, you needed a hot potato. Her granddaughter and I looked at each other both of us non-plussed by this remark. The grandmother then did an impression of someone talking with a hot potato in their mouth. It was very funny. And we all laughed.
But it also made me wonder do we really sound like that? It looked and sounded like someone with a plum in their mouth, as we say in the UK (posh for any reader that doesn't know the phrase). Then I suppose there is also the English phrase when something is a hot potato (ie so controversial no one wants to handle it), but I gather that has another (American?) meaning. Ah well! Who says language is a form of communication?