Can I take two consecutive classes simultaneously? For example, I would like to take Intermediate Spanish I AND Intermediate Spanish II at the same time.
Can colleges, in general, allow that? If my advisor says to me that they think it cannot be done, how can I insist and persuade them (without any illegal activity obviously)? Where do I see these policies?
This question is about US Colleges in general. Not about my specific college.
The policy will be in the prerequisite requirements for a class, in your case, Intermediate Spanish II.  In the U.S., you will find prerequisite requirements in the official catalog of the institution, and probably elsewhere. Somewhere in the official catalog there may be a policy about whether prerequisites can be overridden, and if so how.