Q: term

[Larry Trask]

----------------------------Original message----------------------------
I'm looking for a term.  The phenomenon in question is extremely
familiar, but I don't know of an accepted name for it.
 
The phenomenon is this: a linguistic change which simplifies one
subsystem of a language may complicate another subsystem.
 
A typical example is the history of Spanish mid vowels.  Earlier
Spanish had two low-mid vowels and two high-mid vowels; the low-mid
vowels were *automatically* diphthongized under stress, while the
high-mid vowels were not.  But then the two low-mid vowels merged
with the two higher ones.  This change simplified the phonological
system by removing two phonemes, but it greatly complicated the
morphology: the formerly automatic and transparent diphthongizations
became totally unpredictable and opaque, since some instances of the
new /e/ and /o/ diphthongized while others did not.
 
Does anybody know of an accepted label for this phenomenon, which I
suppose we might elevate to the status of a "principle"?  If not,
wuld anybody like to propose one?
 
Larry Trask
COGS
University of Sussex
Brighton BN1 9QH
England
 
larryt at cogs.susx.ac.uk