Studying in Puerto Rico as a non-native Spanish speaker

A while back, I posted this thread regarding US-accredited universities where the language of instruction is not English. I was under the impression that, and it turns out to be true, that many universities in Puerto Rico are fully accredited US schools on par with UCLA and Virginia Tech that happen to teach in Spanish.

I was fantasizing about going down to PR (yes, I’ve been there, but only as a tourist) and spending a while getting a master’s degree, practicing my Spanish at the same time, and having fun in the tropics, but in reality I probably don’t have the resources to put my life on hold and go to a place where my chances of finding a job are lower than where I am and spend two years there, so this is more a fantasy question.

To what extent is it possible or easy for a non-native Spanish speaker to study at a Puerto Rican university? I found this application which seems to indicate that admission to the nursing program requires competency in English and Spanish, but nothing seems to be stated for the education program. The application also doesn’t tell me the exact level (other than “conocimiento”=“knowledge”) required in the languages or how competency is evaluated (e.g. by coursework or exam). I was looking at the website of Interamerican U and don’t seem to see anything indicating a Spanish language requirement for admission, though some programs have an* English* requirement. Do gringos have to get a qualifying score on a Spanish language standardized test in order to enroll? Is it primarily ad-hoc and you’d better not apply unless you think you can handle being lectured to in Spanish and writing essays in Spanish (i.e. the barriers are practical/de facto)?

I know that, from a legal perspective, US citizens in do not require any sort of migration visa to live, work, or study in PR and so it would seem that the only barriers to attending are getting admission to the school, finding the money and time, and sheer effort and ability.