On 2006-04-06 17:00, Abdullah Konushevci wrote:
> But, what about <mirus, -a, -um> 'strange, special, marvellous' or
> <carus, -a, -um> 'loved' ? I guess that in this case we have much more
> to do with the reduction of first or second element of compound.
The rule is conditioned by syllable structure and phonological weight.
In terms comprehensible to lay people it is as follows:
Syncope takes place if:
(1) *-ros is preceded by a consonant (*sakros > sacer, with -er from a
secondary syllabic rhotic),
(2) *-ros is preceded by a short vowel in a word of three or more
syllables (*fru:giforos > fru:gifer, with analogical /e/; *pueros >
puer; vesperos > vesper, etc.),
[note that your examples don't meet either condition; nor do <ferus>,
<since:rus>, etc.]
(3) exceptionally in <vir>.
If /r/ is the result of rhotacism (< *s), syncope doesn't apply, except,
by analogy, in some compounds with -gerus (< *-gesos), like <armiger>
after <armifer>, but <mo:rigerus>.
See
http://ling.cornell.edu/people/Weiss/CGL_20_Thematic_stems_1_2.pdf
Piotr