A technical term of scientific grammar, applied to the change of a voiced s (z)
between two vowels. In Greek this change is rare, as
in that language the intervocalic s
regularly passed into h
and then disappeared, leaving no trace of its existence, while in Latin
it is regularly changed to r.
(Cf. the Gk. μῦς,
, Lat. mus, mu-r-is:
, Lat. nu-r-us.
) In the dialect of Greek spoken in
Elis, rhotacism occurred instead of loss of s
, and so in some late
Laconian words influenced by the usage of the neighbouring Elis. In Latin rhotacism is a
regular law, for though there are many apparent exceptions to it, examination shows that in
most of these cases the s
was not originally intervocalic or else that
the word is of (a
) foreign or (b
) late origin. For
instance, in causa
is not changed to r
because it represents probably ss
, Cicero having
written it caussa.
In many compounds s
changed to r
because it is to be regarded as an initial rather
than as an intervocalic consonant—e. g. desilio, positura.
many other words the apparently intervocalic s
substitution for another original letter—e. g. esuries
of edo), prosa (provorsa), rosa
, hence cadta
). Such words as basium, casium, gaesum, siser
, and probably asinus
in their origin. The real exceptions to the operation of the regular change to r
do not amount to more than a half dozen, such as vasa,
nasus, agaso, caseus;
and the exceptions are the basis of a special law known as Conway's Law, first set forth by Mr. R. S. Conway, in 1887, as a sort
of corollary to Verner's Law. (See Verner's
.) Conway's Law is as follows: Medial s
between words after an
unaccented syllable became r
, but after an accented syllable it was
retained except when followed by i
preceded by i
or a long vowel or diphthong;
while medial s
before nasals after an unaccented syllable was lost
without compensation; after an accented syllable if arising before the period of rhotacism it
was lost with compensatory lengthening of the preceding vowel (e. g. aenus,
); if arising during the period of rhotacism it became r
(e. g. carmen, verna
Rhotacism in Latin is said to have been effected in the fourth century b. c., as Cicero says (Ad Fam.
ix. 21) that L. Papirius, who was consul
in B.C. 336, was the first of his family to give up the older spelling Papisius. But the
change in general was probably effected earlier, for proper names are notoriously the last to
suffer alterations of form.
Rhotacism occurs also in the Teutonic branches of the Indo-Germanic group of languages. (Cf.
, Engl. iron;
, Engl. blare;
Engl. sing. was
, plur. were.
) The unvoiced s
first passes into the voiced s (z)
and thence to lingual r
, for the position of the vocal organs in pronouncing z
is substantially the same as that required for r.
See V. Henry, Comparative Grammar of Greek and Latin
, pp. 74-76 (Engl.
trans. New York, 1890)
; Roby, Latin Grammar
, vol. i. pp. 98 foll.;
Joret, De Rhotacismo (1875)
; Walter, Rhotacism in
the Italic Languages (1877)
; and Conway, Verner's Law in
Italy (London, 1887)