Post by Peter T. Daniels
How's that? Does <ae> cease being a digraph in <encyclopaedia> vs. <encyclopædia>?
I would have defined a digraph as two glyphs for one sound (e.g. -sh-
and -ee- in "sheep") and a ligature an *optional* joining of two glyphs
into one, irrespective of whether it is one sound or more than one, e.g.
-ﬂ- (the fl ligature). A former ligature whose usage is no longer
optional (except when the media has too restricted a character set) is a
If both "encyclopaedia" and "encyclopædia" are valid spellings in
English, -æ- is a ligature, but Danish -æ- is a glyph.
By this definition, -ß- is clearly a single glyph and not a ligature
although is certainly evolved from one. Yet it has no own place in the
alphabetical order, as distict from Danish -æ- which has.