Thylacism
/ˈθaɪ.ləˌsɪz.əm/noun
A speech disorder in which the sound /s/ is pronounced as or replaced by the “th” sound.
Did you know?Thylacism belongs to the old medical tradition of naming speech disorders with Greek-derived terms such as rhotacism, sigmatism, and lambdacism.
Etymological Timeline
Ancient Greek
Greek
θύλακος (thýlakos)
“A pouch, sack, or sac; the root associated with the term’s unusual name.”
Late Greek / Medical Greek
Greek
θυλακισμός (thylakismós)
“A technical formation referring to the relevant speech peculiarity.”
19th Century
Medical Latin
thylacismus
“A speech defect involving the pronunciation of s as th.”
19th–20th Century
English
thylacism
“The English medical and phonetic term for this pronunciation defect.”
Modern English
English
thylacism
“A rare term for replacing or mispronouncing /s/ with the “th” sound.”