I want to know the answer to the following question:
What was the name of the law that enacted this?
All the background I'm provided with is that "The period since the re-establishment of democracy in Spain—in particular since the Lei de Normalización Lingüística ("Law of Linguistic Normalization", Ley 3/1983, 15 June 1983)—represents the first time since the introduction of mass education that a generation has attended school in Galician (Spanish is also still taught in Galician schools).". Is that enough to answer the question?
Answer: yes