Sorry for jumping in again like this.

Kayl - 1) YES, 2) YES.
Raak - 1) It does involve writing but it is not calligraphy (I think this is slightly different from your interpretation of my answer - 'calligraphy' is not the answer, however, this thing can be expressed using calligraphy. 'Words' is a little more complex - it is involved in words but is not a word if you see what I mean...
Raak - 2) no.
Riff - not really.
Inkspot - not positive or negative.
LotUS - 1) no. 2) no.(Keep jumping in!)

Or if not the alphabet itself, is it a particular letter?
[Raak] It's not religious.

Er, since you've said there's more than one type, maybe I should specify our alphabet, as distinct from, say, the Chinese one.

Raak - no.
Riff - 1) no. 2) yes!
Raak - no.

Riff - no.

Well, I don't want to be a bastard by making 25 more guesses in a row, so I'll just guess "Q", and then I'm going to bed...

Riff - no.
Bearing in mind that everyone should now have an equal chance - from now on I should ration guesses to one at a time - no multiple guesses (e.g. Is it A, C, D, E?) and no posting twice without allowing another player to have a turn. And I'll take first answers only. There is a clue in my first posting of this game...

(B t D) Everyone should observe these conventions anyway.

Presumably the musical connection means it is a letter from A to G...

Recall that the Germans extend the musical alphabet for some superstitious reason that escapes me for the moment.