Due to an InstallAnywhere limitation the installation of StarTeam does not display any language options outside of the current system locale.
To force the install to use a specific language use the "-l" argument. For example,
StCPWin64.exe -l ja
StCPWin64.exe -l zh_CN
To change the language displayed by the CPC modify the StarTeamCP.stjava file, on a 64Bit system it is typically found in
C:\Program Files\Borland\StarTeam Cross-Platform Client 14.0\StarTeamCP.stjava64
Then change the look and feel of the CPC by going to
Tools | Personal Options | Workspace | Advanced | File
It is advisable to avoid "Windows" or "Windows Classic" as some of the required Japanese fonts are missing on English Operating Systems. It is a requirement to have native Japanese Windows or Japanese Multi User Interface (MUI).