When I googled "rhoticism" I hit this page (whose contents I have just moved to another page, rhoticity.html).
The word rhoticism, I am told, does not exist; or
more exactly should not exist.
Wikipedia says of it "Rhoticism
is a word occasionally encountered when one of the following is intended:" - and
then lists rhotacism, rhotacization, and rhoticity. Much as I
like Wikipedia I must demur: this wording seems to imply that I did not intend
to say what I said (and wrote); or that what I said and wrote was somehow a
mistake. But unfortunately the word "rhoticism" does exist, since several
generations of my students have picked it up from me, and so I fear the damage
is relatively widespread. In deference to Miss Candida Fidditch, however, I am
trying to remember to say (and write) "rhoticity" instead of "rhoticism",
although I should be interested to hear an explanation of why one is wrong and
the other right, and it would have to be an explanation which doesn't imply that
Shakespeare was also wrong in his use of a rather large number of his own words. John Wells uses the term rhoticity to refer to whether the English accent concerned
pronounces non-prevocalic r or not. The
word rhotacism means “how the r is pronounced” in any language. Wells
also uses the term rhotacization to mean “r-colouring” of a vowel.
So let's try to forget "rhoticism", which seems to have the same
status as Febuary and longditude .... PK