English as a medium of instruction is a hot topic again these days. Philippine Commentary has posted several times, this being the most recent.
As with many other issues, the market-oriented approach seems best. (Which allows me to get away with using my comment as a post in this here economics blog):
It's time to depart from the rhetoric of cultural imperialism and legalism, and shift towards a pragmatic approach to this issue. I was intrigued by Tan's claim that students learn faster with the mother tongue. Not being an education language expert, I did a little googling and found that, voila (Pranses iyan, uy), there is good evidence that mother tongue teaching is associated with better education outcomes, compared to second (or third) language teaching. However there is by no means a consensus - mainly because the "all other factors constant" condition is difficult to meet.
The best paper I've read about the subject is found here. Paper No. 9 argues for a "market-oriented" approach. Rather than a dogmatic, one-size-fits-all approach, why not devolve the language issue to the schools? (And that's not the only choice that needs to be devolved. I happen to think the entire public school system should be privatized and education support extended through school vouchers. But that's another debate). Public resources can indeed be devoted to production of mother tongue learning materials. But there should be no ridiculous language quota one way or another. And note that I am not talking about Tagalog. All the studies have been about the "mother tongue" - which for most Filipinos, is certainly NOT Tagalog (which is my mother tongue).