sigma + -ism
sigmatism (countable and uncountable, plural sigmatisms)
- A lisp.
- Defective pronunciation of sibilant sounds.
2007 October 30, C. Claiborne Ray, “Whence the Whistle?”, in New York Times:
The flaw in pronouncing a sibilant S, which speech therapists call sigmatism, can follow even minor changes to the way the tongue aligns with the teeth.