Lisp

Background
A lisp (O E wlisp, stammering) is a speech impediment, historically also known as sigmatism. Stereotypically, people with a lisp are unable to pronounce sibilants (like the sound Voiceless alveolar fricative), and replace them with interdentals (like the sound Voiceless dental fricative), though there are actually several kinds of lisp. The result is that the speech is unclear.


 * "Interdental" lisping is produced when the tip of the tongue protrudes between the front teeth and "dentalised" lisping is produced when the tip of the tongue just touches the front teeth.


 * The "lateral" lisp, where the and  sounds are produced with air escaping over the sides of the tongue, is also called 'slushy ess' or a 'slushy lisp' due to the wet, spitty sound. The symbols for these lateralized sounds are in the Extended International Phonetic Alphabet for speech disorders,  and.


 * Finally there is the "palatal lisp" where the speaker attempts to make the sounds with the tongue in contact with the palate.