>>Likewise, deletion is more common than epenthesis, but both _may_
>>happen, as Richard has pointed out.
> Isn't it so that it _must_ happen?
Roughly speaking, what may happen must happen, sooner or later.
> I would think the true "axioms" of sound change are:
> 1) there are no "sinks"
> 2) there are no "sources"
> Every phoneme /x/ must have at least one out-transition (/x/ -> /non-x/)
> and at least one in-transition (/non-x/ -> /x/). Otherwise, the sources
> would have long ceased to be possible phonemes, and sound-change would have
> stopped altogether as soon as all phonemes had been attracted to the sinks.
> Now, since we know that for the null phoneme, sound changes /x/ -> /0/
> exist, there must also be transitions /0/ -> /x/ (something from nothing).
> To be sure, epenthesis is not the main mechanism (which I think is word
> composition, operating at the lexical/semantic level, above the
> phonological level).
Very good points. One might note that there are environments in which
epenthesis can be considered natural for reasons that have to do with
the neuromuscular control of the vocal tract (e.g. -nR- > -ndR-) or with
perceptual factors (e.g. -CR > -C&R).