The Collaborative International Dictionary
Wharl
Wharl \Wharl\, Wharling \Wharl"ing\, n. A guttural pronunciation of the letter r; a burr. See Burr, n., 6.
A strange, uncouth wharling in their speech.
--Fuller.
Wiktionary
wharl
n. (context medicine English) A rattling or uvular utterance of the r-sound.