Let's not forget our lonely Akhmimic dialect. From the Coptic Encyclopedia:
"Akhmimic ads the alphabetic symbol |, the postpalatal spirant /x/ (or h, [x2] from the Egyptian or h); in P, the symbol for this is q."
This is the same letter as the Bohairic q. However, it is not pronounced with the uvular sound /x/ or /kh/ sound, but the postpalatal /h/.
And then there is Proto-Theban (Dialect P). It adds a letter from Greek origin, (the grapheme looks like "k" with a tail on the bottom stroke). The Sahidic =n[i in Dialect P is =nk. And then Dialect P has no less than 10 letters taken from Demotic Egyptian. Many have very strange looking graphemes.
Although your question didn't imply it, there are some letters that have one sound in one Coptic dialect and a different sound in another dialect. So to get a /k/ sound in most Coptic dialects, you use k. In Dialect P, you use ≥ to get that same /k/ sound. Since Dialect P is so weird, we can use another example. To get a /f/ sound in most Coptic dialects, you use f. In Dialect G, you use v to get that same /f/ sound. Do these count as separate letters?
The moral of this post: Coptic is more than Bohairic (whether you call it Old Bohairic or Greco-Bohairic) and Sahidic. The language is so rich. Indigenous Copts only consider the Bohairic dialect as Coptic and (some?) Coptic scholars only consider Sahidic as true Coptic. It's time we educated ourselves and learn the remaining 99% of Coptic that is out there that most people don't know exists.
Comments
"Akhmimic ads the alphabetic symbol |, the postpalatal spirant /x/ (or h, [x2] from the Egyptian or h); in P, the symbol for this is q."
This is the same letter as the Bohairic q. However, it is not pronounced with the uvular sound /x/ or /kh/ sound, but the postpalatal /h/.
And then there is Proto-Theban (Dialect P). It adds a letter from Greek origin, (the grapheme looks like "k" with a tail on the bottom stroke). The Sahidic =n[i in Dialect P is =nk. And then Dialect P has no less than 10 letters taken from Demotic Egyptian. Many have very strange looking graphemes.
Although your question didn't imply it, there are some letters that have one sound in one Coptic dialect and a different sound in another dialect. So to get a /k/ sound in most Coptic dialects, you use k. In Dialect P, you use ≥ to get that same /k/ sound. Since Dialect P is so weird, we can use another example. To get a /f/ sound in most Coptic dialects, you use f. In Dialect G, you use v to get that same /f/ sound. Do these count as separate letters?
The moral of this post: Coptic is more than Bohairic (whether you call it Old Bohairic or Greco-Bohairic) and Sahidic. The language is so rich. Indigenous Copts only consider the Bohairic dialect as Coptic and (some?) Coptic scholars only consider Sahidic as true Coptic. It's time we educated ourselves and learn the remaining 99% of Coptic that is out there that most people don't know exists.
Again another detailed and well written answer that answers my question and more, thank you Remnkemi. :D