It seems to me that Attic should be viewed as a dialect of Ionic with Dorian influences. Instead, textbooks seem to treat it like it’s a language in it’s own right. Does anyone here know of any textbooks that explain the Ionic and the Doric and, through them, the Attic?
Or, failing that, how can I find out more about these other dialects?
I have never seen, or heard of, a Classical Greek textbook teaching by anything other than Attic, Koine or Homeric. This has mostly to do with numbers I think - there’s plenty of literature in all these dialects, though of course Koine has other historical pressures making it popular. Most of what we know from the other dialects comes from stone tablets (decrees, treaties, etc) from the many Greek cities and colonies.
Except for Herodotus in Ionic, there simply isn’t major literary representation of the other dialects. If someone digs up all 10 books of Sappho’s poetry in the sands of Egypt at some point that might change, and Lesbian Aeolic could become more popular. But I doubt it’d ever be the base dialect for a course of study.
Or, failing that, how can I find out more about these other dialects?
Is this just curiosity, or do you have a particular goal in mind?
If you can, hunt down Buck’s Greek Dialects. It has lots of interesting stuff along with lots of examples, which are all from public monuments from all over.
At Aoidoi.org I have quick articles on Lesbian Aeolic and the choral Doric used by the choral poets, but this is a constructed literary dialect.
Finally, most student editions of Greek authors who use a dialect other than Attic or Ionic will have an introduction to the dialect. The Cambridge green-and-yellows for both Pindar and Theocritus devote several pages to it.
As an example…
In A COMPENDIUM OF ANCIENT GREEK PHONOLOGY it says:
“Indo-European long *a survived in most Greek dialects, but in Attic-Ionic it evolved into a long flat e (English drag), which subsequently became assimilated to long open e (French tête), spelled η. In Ionic dialect this change of quality was carried through uniformly, while in the Attic dialect it was inhibited when the original *α was preceded by ε, ι or ρ.”
JWW’s book mentions those same rules regarding eta and alpha, but without reference to the reason behind them. Inevitably, I forget rules like that quickly if the reasons behind them aren’t given (even if the reasons are just as arbitary as the rules themselves). For some reason, my mind works like that.
I would undoubtedly find taking a pan-Hellenic view of the language to be easier than treating one dialect like it’s a language that exists in a vaccum; because I could then see the patterns more easily and put them in their historical context.
What were the Byzantines doing, when they were supposed to copying this stuff down? 
Is this just curiosity, or do you have a particular goal in mind?
Although it seems like biting off more than I can chew, I think it’ll actually be easier to learn this way. However, I have no serious goal in mind.
Also, I know there’s a lot of ancient Greece that isn’t Attica; so my goal was always to learn Ancient Greek, not just Attic. But, because most surviving texts are in Attic, it is my main interest. Therefore the other dialects I most want to know about are Doric and Ionic.
If you can, hunt down Buck’s > Greek Dialects> . It has lots of interesting stuff along with lots of examples, which are all from public monuments from all over.
Thanks, I’ll look for that.
EDIT: Link added
I’m suprised to hear that there isn’t much surviving literature in Doric, considering the number of powerful, independent Dorian cities.
Also, I know there’s a lot of ancient Greece that isn’t Attica; so my goal was always to learn Ancient Greek, not just Attic. But, because most surviving texts are in Attic, it is my main interest.
most greek authors don’t use just one “pure” dialect. e.g. pindar brings in doric words and boeotian aeolic words… herodotus has lots of non-ionic words apparently… basically none of the “attic” writers, except for the speechwriter lysias, just used the attic dialect, but rather brought in words from other dialects all the time. you don’t get much “pure attic” at all in ancient greek, when you start reading the originals. it makes sense, because they travelled all around to learn their writing skills… pindar went to athens to learn how to write poetry… plato started out as a playwright and so he would have written lyric parts in the doric dialect… xenophon spent a large chunk of his life away from athens…
Shurely they would have had to pick one dialect when it came to word endings and such?
(Except for poets, who made up their own rules. 
)
i think they used spellings from different dialects for certain words… in commentaries on attic authors, like thucydides, they list at the start non-attic spellings used throughout.
it’s not uncommon today either… you see people in australia happily writing colour (instead of us color) but also using the us -ize ending, eg standardize, instead of our/uk standardise (because lots of people install the us spellchecker on microsoft word by default…). and when it comes to words like jail/gaol, grey/gray, metre/meter, it gets pretty arbitrary…
I think variant spellings are less of a big deal, in English, because words aren’t spelled the way they are pronounced.
However, that said; no Australian must ever spell “colour” without a ‘u’!!! 
The other things I’m not fussed about, as long as they don’t roll their 'r’s.