From Elaine Yeung's review of No Strings Attached: "In addition, it is quite hard to picture a Filipino setting where all the characters speak in perfectly straight English."
Elaine brings up an excellent point, which I wanted to blog about, in case an international reader wanders over.
I made a deliberate decision when I prepared my very first manuscript for publication that I would write it mostly in English. In reality, middle-class twenty-something women living and working in Metro Manila would be at least bilingual, speaking Filipino and English (or "Taglish") with ease at home, at work, with friends. But this doesn't yet capture exactly how we speak -- I know people who speak Bisaya, Ilonggo, and other regional languages at home. The slang I speak with close friends can be hard to understand, and I know because I have to translate sometimes for my husband later, even though we heard the exact same thing at dinner.
It's difficult to get that absolutely note-perfect, for me. International readers would notice that I do have the stray Tagalog word here and there, though, because I chose to retain some "untranslatables." Maybe it provides a hint of local color to some, but it doesn't do justice to the way we actually do use our native languages. I really just use them to avoid a more awkward English translation, so I say "kuya" rather than "older guy who isn't related to me but could be older brother also" or "bulalo" instead of "beef bone marrow soup."
The decision to go mostly-English has to do with a lot of things, but first of these is that if I did it any other way, I wouldn't be able to finish anything. I've tried, and the pressure to "get it right" just kills every draft, every time. So, kudos to writers who can craft characters and give them the right slang and language and make it sound real.
The upside of my earlier decision? The stories produced in this way found an international audience. I wonder if it's possible to have both (the correctly-represented languages AND the international audience) but since I haven't successfully finished an attempt, I don't personally know.