Once choosed first language for iSmartDiag scan tool, switch to other language software is allowed?

 No, you can't.

As soon as we are registering the scan tool, it requires users to select needed langauge before downloading diagnostic software, for example, if I am selected English as my first language.

The users can download English software without any problems, however other languages software isn't allowed to download once we are selected English language, when we are switch language to Spanish or Portuguese, the software will be empty.