Morphology: Formation of perfect stem

 

Verbs starting with a double consonant:
ε added to the beginning of the stem
 
We've only seen 2 verbs like that:
ζητέ-ω - ἐζήτηκα
πταί-ω - ἔπταικα

You'll come across some more, though not many.

 

 
Verbs starting with a vowel or a diphthong.
The initial vowel is lengthened.
 
How do we lengthen a vowel? According to what rules?
Easy:
  • omega ω and eta η, being long already, won't change.
    No noticable augment! Luckily we don't rely on the augment alone to know whether we are talking past, the endings also help, usually. If not, there is always the general context to consider. That is why we always know when Homer (and a few other Greek authors) refer to the past, even though they do not use past augments much, if at all. Context does [most] always tell. And the verb-endings of course.
  • short ῐ and short ῠ just lengthen their sound to ῑ and ῡ (you'll hear the difference quite clearly)
  • Leaves alpha α, epsilon ε and omicron ο.
    • Both α and ε change to η (though in some rare cases ε lengthens into the diphthong ει. )
    • omicron ο changes to omega ω.
End of story.
End of story? What happens to diphthongs? Nothing much, it is the initial vowel that changes, nothing else. Except...
A long vowel iota diphthong isn't a real diphthong anymore (difficult to pronounce!) so the iota sound has a tendency to disappear totally and the iota becomes subscript: to show that it is there, even if unnoticed by the ear:
ᾱͅ, ῃ and ῳ