Lisping is a common type of orofacial myofunctional disorder. It describes improper positioning of the tongue, which affects the production of certain sounds.

Generally, it affects “s/z” and “sh/ch/j” sounds; “t,” “d” and “n” sounds may also be affected. It is common in preschool-aged children who haven’t yet developed mature articulation patterns, but may persist into adulthood. A frontal lisp tends to replace “s/z” and “sh/ch/j” sounds with “th,” while a lateral lisp tends to make them sound more “slushy” or “wet.” With a frontal lisp, tongue thrust can be observed when the person swallows and even when they’re resting.