Puerto Rico — Language Policy

In 1902, four years after Puerto Rico became a U.S. “dependency” in the Spanish American War, the United States declared the island officially bilingual. Public business would be conducted in both Spanish and English. In practice, however, the latter predominated. Until Puerto Rico was granted a measure of political autonomy in 1948, colonial officials rarely bothered to learn the language of the colonized. Meanwhile, they sought to impose English on Puerto Ricans through a variety of coercive practices in the schools. Yet half a century of English Only instruction did not succeed in displacing Spanish – only in depriving generations of schoolchildren of a meaningful education. (Language Policy — Puerto Rico)

The law of 21 February 1902 law ordered the use of both English and Spanish as co-official languages in the government of Puerto Rico also made English the obligatory language of instruction in Puerto Rican high schools. This practice, however, was officially modified in 1948, when English was required in schools only as a second language, and not as a language of instruction in all academic high school subjects. The new 1948 practice was the result of a 1947 decree by Education Commissioner Mario Villaronga ordering that Spanish be the language of instruction for all but the English course. The decree is binding only on public schools and private schools continue the use of English. (English language in Puerto Rico – Wikipedia)