rhotacism
n. ரகரமோகம்.
Rho"ta*cism, n. Etym: [Gr. "rwtaki`zein to use the letter r (r) overmuch: cf. F. rhotacisme.] Defn: An oversounding, or a misuse, of the letter r; specifically (Phylol.), the tendency, exhibited in the Indo-European languages, to change s to r, as wese to were.