From: Mark Odegard
Message: 1434
Date: 2000-02-07
http://www.britannica.com/bcom/eb/article/3/0,5716,119413+13 ,00.html
Paul Cubberley, in his chapter in Daniels and Bright's The World's Writing System, p. 346, seems to believe the extra consonants were based on Armenian exemplars, while the extra vowels were based on Greek variants.
He gives this etymological note on p. 347: "Glagolitic, (glagólitica) from glagol-, (word, say').
Mark.