James Tauber has published a short video explaining the accentuation of Ancient Greek words in a way that is more precise than what is found in beginning grammars that deal with the issue. If you don’t follow the argument fully, just watch a second time.
If you have never studied Greek accents before, here are some terms that may help you understand the video:
ultima = the last syllable in a Greek word
penult = second to last syllable
antepenult = third to last syllable
oxytone = an acute accent (´) on the ultima
paroxytone = an acute accent on the penult
proparoxytone = an acute accent on the antepenult
perispomenone = a circumflex accent (῀) on the ultima
properispomenone = a circumflex accent on the penult
Thank you, James.