I wish my university had a course in this -- it's quite fascinating (and I learn things about ten times more easily if I can understand why they work the way they do.)
Can you recommend a book on how all these sound changes, etc. happened in Greek? Part of what's frustrated me about the language is its seeming randomness, and I'd like to try to get to the bottom of why it works the way it does.
I don't have anything specific to recommend off hand, other than perhaps a good grammar like Smyth which should cover the basics. A comparative grammar of Greek and Latin might also be particularly suitable for this purpose, but before purchasing anything you'll probably want to peruse it first in your university's library.
What textbook are you using, btw? I remember suggesting Groton to you in the past, but I think that was before you decided to return to university. I recommended it to you precisely because it goes into a lot of depth for an introductory textbook, which is something I know you appreciate. I get the sense, judging by what you've said so far, that your current textbook is somewhat lacking in this regard, which is unfortunate.
Another question. The 1st/3rd declension adjective ταχύς/ταχεῖα/ταχύ was introduced in the same chapter. I understand the feminine forms well enough, but the masculine/neuter mystify me. To be precise:
- why does it have two different stems (one with υ and one with ε)?
I'm not sure exactly, but it seems it had something to do with an original digamma in the stem, which was maybe originally just a vocalization of υ into a semivowel, making it either ταχέϝ- or ταχύ-. Of course the digamma was later lost, but it seems to have prevented contraction even after its loss in some cases, probably because most such contractions happened before its disappearance.
- why does it contract in some cases (e.g. dative singular) but not others (e.g. genitive singular)?
I imagine it's just because the contraction of ε + ι to ει was more straightforward than the other kind of contractions in Attic. I believe the dative could be εϊ in Epic, so there's that.