> From: ISO 639 Joint Advisory Committee [mailto:[log in to unmask]] On Behalf Of > Michael Everson > >Perhaps "zzz" for this special-purpose code? > > Well, in ISO 15924 Zzzz is "Code for uncoded script" which still > implies "script" If 15924 is used as an example, then perhaps "zxx" for non-linguistic content (analogous to "zxxx" for unwritten languages). Peter Constable