Linguistic contortion is de rigueur for any central banker. Federal Reserve supremo Ben Bernanke, however, took it to the next level with his speech to the Chinese Academy of Social Sciences on Friday.

The original text contained potentially inflammatory references to the “subsidy” provided to China’s booming export industries by an undervalued renminbi. When he actually spoke, however, Mr Bernanke mysteriously softened his line, talking of a “distortion” instead. The Fed said his change of words was “spontaneous” – a remarkable claim to make about a central banker.