In 601 it says that omicron, by compensative lengthening, becomes oυ, but 681 reads that δαιmov becomes daimων and γεροντ becomes γερων (which is what I thought it should do). Which is correct? Is there something here that I am not understanding correctly?
601 also says that epsilon becomes ει. Why doesn’t it become η?
Thank you!! This is a wonderful website for self-learners.
Have you checked Smyth?
Notice section 37. Also, he specifically says that the lengthening from ο to ου and from ε to ει are spurious in note c of that section. Normal lengthening of ε is to η and of ο is to ω.
In section 242, he addresses the lengthening of third-declension noun stem vowels.
(Curiously, why does your μ come out as m in your post?)
No, I am not familiar with Smyth.
I think I was confusing compensative lengthening with third declension stems ending in rho, sigma, and nu lengthening their last epsilon to eta or last omicron to omega. Sometimes my head gets spinny trying to absorb and understand all this.
However, are you saying that what Pharr writes in 601 is indeed incorrect? That in compensative lengthening, epsilon should become eta (not ει) and omicron should become omega (and not ου)? If so, I’ll correct it in my book.
Thank you!
Aimee
Not at all. There are cases, like masc. acc. pl. of 2nd declension, where o turns to the (spurious)
diphthong ου (-ον-ς > -ους), and there are others, like noun stems ending in ν and οντ,
where o turns to ω (δαιμον* > δαίμων; γεροντ* > γέρων, but note dat. pl. γεροντ-σι* > (ντ drops) > γέρουσι).
With ε, there is λιμεν* > λιμήν, and there is ἐ-μεν-σα* > ἔμεινα (aorist of μένω; example from Smyth).
You’ll have to correct that, too. 
Smyth is essential.
Smyth for PDF download from Textkit - link
Same from Internet Archive - link
There’s a newly updated online version, but I can’t seem to find the link that I had for it. I’ll look around. If I find it, I’ll post it here.
Regards,
Jai
Greek spelling rules changed through time. Originally ε meant any E-type sound, and ο meant any O-type sound, and η was called “heta” and meant H.
With time, and influence from the H-dropping Ionic dialect, Attic usage changed to:
ε = closed E sound as French é or German long ‘e’
ει = diphthong
η = long open E (since Indo-European ‘ē’ had become Ancient Greek long open E)
ο = closed O sound
ου = diphthong
ω = long open O (since Indo-European ‘ō’ had become Ancient Greek long open O)
ε and ο could be short (Indo-European original) or long (from Greek-period contraction, or as compensation before N dropping before S)
Time passed and the diphthongs ει and ου became long closed vowels. So people started writing the long closed vowels as ει and ου, to distinguish from the short vowels. For example, ου is the original diphthong in ἀκουω, but long closed vowel in the common genitive -ου.
We thus have:
ε = closed short E sound as French é
ει = diphthong, or long closed vowel (if you can remember which is which in which words)
η = long open E
ο = short closed O sound
ου = diphthong, or long closed vowel (if you can remember which is which in which words)
ω = long open O
The lengthening in daimων is “vrddhi” that happened in Indo-European times.
Examples of o becoming ou happened in Greek times.