Most Filipinos would be happy to hear you speak Filipino (Tagalog) and might even switch to English for your convenience. Some might not understand the language and will respond with a smile on their face (I don't know); don't take it the wrong way. We're just reticent. It is a sign of great respect and cares that you choose to address us in our native tongue rather than force us into learning yours.
Filipinos are generally more flattered than insulted by an offer to try their native language, so it should be relatively easy as long as you pronounce the unfamiliar words accurately through adequate study beforehand. You can also say thank you or sorry after addressing someone in Tagalog, as words exist in the language.
If you want to speak Filipino (Tagalog), there is a pretty good chance your interlocutor will be highly receptive and generally pleased to hear it. However, some people might not understand what you're saying. So again, it's a sign of care and respect that you've chosen to address them in their native tongue rather than force them into learning yours.
