Turning Japanese was a 1981 hit by a U.K. pub-rock band called The Vapors. According to the lead singer, the title means "turning into something you didn't expect to." In the financial markets, the phrase has become shorthand for an extended period of economic stagnation, on the lines of the "two lost decades" that followed on from the collapse of Japan's bubble economy in 1990.
As with the lyrics of the song, the initial idea was that the phenomenon - also known as "Japanization" and "Japanification" - was bizarre and highly unlikely to occur in Western countries. No longer. Low growth and rock bottom interest rates have characterized the economic landscape in much of the developed world since the global financial crisis of 2008.