How do I pronounce murciélago, and why?
According to Rules applied to the separation of syllables , "i" is a a closed vowel, and "e" is an open vowel, so without an accent, it would be a diphthong.
According to this comment "ié" is also a diphthong.
How is the word broken up, and how is it stressed? I would strongly assume that if there's an accent mark, then that must be stressed, but listening to various pronunciations on forvo, it seems (at least to this English-speaking brain) that most of the time they say "mur ci e la go", with the stress seeming to be on a "ci" syllable rather than on the "e".