Lisp

A lisp is a speech impairment in which a person misarticulates sibilants (s, z, ts, dz, ʃ, ʒ, tʃ, dʒ). These misarticulations often result in unclear speech. A frontal lisp occurs when the tongue is placed anterior to the target. Interdental lisping is produced when the tip of the tongue protrudes between the front teeth and dentalized lisping is produced when the tip of the tongue just touches the front teeth. The transcription in the International Phonetic Alphabet for interdental sibilants is [s̪͆] and [z̪͆] and for simple dental sibilants is [s̟] and [z̟]. When a fronted lisp does not have a sibilant quality, due to placing the lack of a grooved articulation, the IPA transcription would be [θ, ð] or variants thereof. A occurs when the [s] and [z] sounds are produced with air-flow over the sides of the tongue. It is also called "slushy ess" or a "slushy lisp" in part due to its wet, spitty sound. The symbols for these lateralised sounds in the extensions to the International Phonetic Alphabet for disordered speech are [ʪ] and [ʫ]. A occurs when part or the entire air stream is directed through the nasal cavity. The transcription for sibilants with nasal frication in the extensions to the IPA is [s͋] and [z͋]; simple nasal fricatives are [s̃] and [z̃]. A strident lisp results in a high-frequency whistle or hissing sound caused by stream passing between the tongue and the hard surface. In the extensions to the IPA, whistled sibilants are transcribed [s͎] and [z͎]. A palatal lisp is where the speaker attempts to make a sibilant while the middle of the tongue is in contact with the soft palate, or with a posterior articulation of the sibilant. The latter may be transcribed [s̠] and [z̠], [ʃ] and [ʒ], or the like. Successful treatments have shown that causes are functional rather than physical: that is, most lisps are caused by errors in tongue placement or density of the tongue within the mouth rather than caused by any injury or congenital deformity to the mouth.