Stress on the second syllable, glottal stop on the third. Bat-ha-lâ.
Not much is known about Bathalà (or at least, I don’t know much about him), but he seems to have been a very important deity to the pre-christian Tagalog tribes that, even today, Bathalà is the preferred poetic term for god (as a common noun) and “God” as in the divine father of Jesus.
Owing to the country’s deep but forgotten Hindu past, Bathalà seems to come from Sanksrit “bhattara” (noble lord), akin to Malay “betara” (holy), a title applied to the greater Hindu gods of the ancient Majapahit empire.
According to an excerpt from the Boxer Codex (1590b, 367):
They said that this god of theirs was in the air before there was heaven or earth or anything else, that he was ab eterno (from eternity) and not made or created by anybody from anything, and that he alone made and created all that we have mentioned simply by his own volition because he wanted to make something so beautiful as the heaven and earth, and that he made and created one man and one woman out of the earth, from whom have come and descended all the men and their generations that are in the world.
Bathala, though, seems to have been a creator much like Brahma (he is called Maykapál or Maker). Having fashioned the world, he retired to kaluwálhatían (a place like Olympos) and assigned the ordering and governance of the world to younger deities called anito or diwatà. He did not seem to receive regular cultus as they did, being removed far from humanity and the natural world.
He is similar to Kan-laón and Gugurang, other creator deities known to pre-colonial Filipinos.