I installed the VMware vSphere 5 Client in French on my Windows 7 virtual machine. Since I wanted to take screenshots, I had to start it in English. Even when not installed in English, you can still run the English version. Just run:
"C:\Program Files (x86)\VMware\Infrastructure\Virtual Infrastructure Client\Launcher\VpxClient.exe" -locale en_US
Worth a post?
Source: VMware KB: Changing the language used by vSphere Client