I tried googling this and spoke to several people in the island but wasn't able to find a good response. Most other colonies speak the language of their colonizers, like Belize. And other territories of the US that belonged to France , Spain or Mexico on the past now fully speak English.
There was a big push from the federal government to institute english and their culture in the island in the early 1900s but it failed? My friends in San Juan said that people took actual steps to preserve their tradition but couldn't name which or by whom or why, so I would love to hear more details about this. Thanks!
This is because puerto rico was not originally a US or English colony! It was apart of the group of Islands that originally spoke using the Taino group of languages, and when it was colonized the shift was made to spanish (this would have been a lot more forceful so to say than the push in the 1900's by the US, hence why spanish is so prevalent, but english not as much) also, due to its long standing status as a spanish colony and its literal spanish name being 'rich port' There was likely a large amount of families who immigrated and then tied themselves in with the local culture, making spanish even more relevant there, since a good portion of the population has spanish ancestry. The Taino language is also still used intermittently, but not with a frequency anywhere near spanish. Spain has a very rich cultural tradition that is connected closely with the language, so i would not be surprised if this phenomenon continued in PR>