To my ear, the Thai pronunciation of Pattaya comes closest to PAH-tah-yaah, with the 1st syllable regular length and emphasized, the second so short it almosts sounds like an aspirated "t" (hence the occasional spelling as Patthaya), and the third syllable elongated. Many foreigners seem to pronounce it puh-TAI-uh, including some of the english language announcers on the Pattaya news channels, but I can't recall ever hearing a Thai pronounce it that way.