The Problem with Greek vowels

• Lengthening of 1 vowel:
  In some circumstances a short vowel lengthens its sound and becomes long.
  1. temporal augment, affects all vowels.
  2. aorist, future and perfect of contract verbs, i.e. verbs with a stem ending in: -α, -ε or -ο.
      
     
• Meeting of 2 vowels:
  • They ignore each other: 2 syllables
  • The 1st disappears: elision
    
  • They join to create a diphthong: combination of vowel plus ι or υ
  • They combine in other ways: contraction
    They combine in other ways: crasis

1. The 2 vowels belong to 2 different words
• elision
• crasis: (mingling) The 2 words are "mingled" into one: the end vowel (or diphthong) of the first word is dropped and a hook (called by its Greek word coronis) put over the vowel (or diphthong) of the original 2nd word.
2. The 2 vowels are adjacent within a word.
   • 2 words: the end vowel of the first word is dropped in pronunciation and replaced by an apostrophe in writing. Except of course if that vowel was long. Long vowels are never dropped.
     2 vowels following each other inside the same word.
     This is where it gets interesting. We have either
     • 2 separate syllables
     • elision
     • combination
     • contraction
     • Combining: producing diphthongs when followed by i or u
     • Contracting: vowel followed by other vowel (except i or u