It is called vSphere client locale forcing mode. It is a new feature added to 4.1 which forces the vSphere client to provide the interface text in English even if the machine is not running English.
Just type the below command line:
vpxClient -locale en_US
This won’t change the actual running machine, nor change the settings such as time or other locale settings. This is very helpful since 4.1 comes in the following languages now:
- English, French, German, Japanese, and Simplified Chinese
Source: Release Notes