Mispronunciation of "r"

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
1830, from Modern Latin rhotacismus , from Greek rhotakizein , from rho "the letter -r-," from Hebrew or Phoenician roth . Excessive or peculiar use of the -r- sound (the "burr"), especially the conversion of another sound (usually -s- ) to -r- ; as in ...

Wiktionary Word definitions in Wiktionary
n. 1 An exaggerated use of the sound of the letter R. 2 (context countable linguistics English): A linguistic phenomenon in which a consonant changes into an R, such as Latin ''flos'' becoming ''florem'' in the accusative case. 3 inability to pronounce ...

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Rhotacism \Rho"ta*cism\, n. [Gr. "rwtaki`zein to use the letter r ([rho]) overmuch: cf. F. rhotacisme.] 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 ...

Wikipedia Word definitions in Wikipedia
In medical contexts, rhotacism is the inability or difficulty in pronouncing the sound r. Thus, many speech pathologists call this problem de -rhotacization, because the sounds lose their rhotic quality rather than becoming rhotic. The rhotic sounds are ...