Santorum tells Puerto Ricans to speak English if they want to be a state.

[True Federalist (진정한 연방 주의자)]

While de jure there is no requirement that Puerto Rico speak English to obtain statehood, de facto there is.  The fact that Puerto Rico is not integrated into the mainland culture (of which English as the dominant language is a part) to anything even close to the degree that Hawaii was at statehood is one reason why there is no push from the Federal side for them to become a State.