A question for Urban:
Ladefoged & Maddieson (following Lindblad) describe two
variant articulations of Swedish [ɧ]. One (actually second in their order of
exposition) is very similar to what you described in your posting on "phonetic
curiosities". The other is defined as a strongly rounded
labiodental velar or velarised voiceless fricative. In simpler
terms, they describe it more or less as [f] and [x] articulated
simultaneously, with strong lip protrusion. There is more detail in the book but
I haven't got it with me now and am quoting from memory; I can provide a
verbatim quotation if necessary. It appears from the description that in this
variant the labiodental articulation is primary and the velar
constriction serves to colour to the sound dark. Can you comment on
this?
I also wonder if the early Modern English confusion between
[f] and [x] (as illustrated by the pronunciation of enough
or laugh) did not result from the existence of a similarly
complex fricative in English once upon a time. And of course Ukrainian could be
another case.
Piotr