|Classification and external resources|
- "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. This is also referred to as a "frontal lisp," as the sound is produced anterior where it is expected.
- The "lateral" lisp is where the [s] and [z] sounds are produced as a result of air-flow being pushed over the sides of the tongue. It is also called 'slushy ess' or a 'slushy lisp' due to the wet, spitty sound. This is fine when it comes to producing the "L" tones, but it sounds slushy or wet when trying to make out the "S" tone. The symbols for these lateralised sounds are in the Extended International Phonetic Alphabet for disordered speech ([ʪ] and [ʫ]).
- A "nasal lisp" occurs when part or the entire air stream is directed through the nasal cavity.
- A "strident lisp" results in a high-frequency whistle of hissing sound caused by stream passing between the tongue and the hard surface.
- A "dentalized lisp" does not have a sibilant quality, resulting from occluding the breath stream in the oral cavity, usually by placing the tongue too far forward of not allowing for a narrow, groved passageway for the breath stream to pass between the tongue and alveolar ridge.
- A "palatal lisp" is where the speaker attempts to make the sounds with the middle of the tongue coming into contact with the soft palate.
Successful treatments have shown that causes are psychological rather than physical; most lisps are caused by errors in tongue placement within the mouth. The most frequently discussed of these problems is tongue thrust in which the tongue protrudes beyond the front teeth. This protrusion affects speech as well as swallowing and can lead to lisping. Ankyloglossia or tongue-tie can also be responsible for lisps in children. However it is unclear whether these deficiencies are caused by the tongue-tie itself or the muscle weakness following the correction of the tongue-tie. Overbites and underbites may also contribute to non-lingual lisping. Temporary lisps can be caused by dental work, dental appliances such as dentures or retainers or by swollen or bruised tongues.
With an interdental lisp, the therapist teaches the child how to keep the tongue behind the two front incisors.
One popular method of correcting articulation or lisp disorders is to isolate sounds and work on correcting the sound in isolation. The basic sound, or phoneme, is selected as a target for treatment. Typically the position of the sound within a word is considered and targeted. The sound appears in the beginning of the word, middle, or end of the word (initial, medial, or final).
Take for example, correction of an "S" sound (lisp). Most likely, a speech-language pathologist (SLP) would employ exercises to work on "Sssssss." Starting practice words would most likely consist of "S-initial" words such as "say, sun, soap, sip, sick, said, sail." According to this protocol, the SLP slowly increases the complexity of tasks (context of pronunciations) as the production of the sound improves. Examples of increased complexity could include saying words in phrases and sentences, saying longer multi-syllabic words, or increasing the tempo of pronunciation.
Using this method, the SLP achieves success with his/her student by targeting a sound in a phonetically consistent manner. Phonetic consistency means that a target sound is isolated at the smallest possible level (phoneme, phone, or allophone) and that the context of production must be consistent. Consistency is critical, because factors such as the position within the word, grouping with other sounds (vowels or consonants), and the complexity all may affect production.
Another popular method for treating a lisp is using specially designed devices that go in the mouth to provide a tactile cue of exactly where the tongue should be positioned when saying the "S" sound. This tactile feedback has been shown to correct lisp errors twice as fast as traditional therapy.
Using either or both methods, the repetition of consistent contexts allows the student to align all the necessary processes required to properly produce language; language skills (ability to formulate correct sounds in the brain: What sounds do I need to make?), motor planning (voicing and jaw and tongue movements: How do I produce the sound?), and auditory processing (receptive feedback: Was the sound produced correctly? Do I need to correct?). A student with an articulation or lisp disorder has a deficiency in one or more of these areas. To correct the deficiency, adjustments have to be made in one or more of these processes. The process to correct it is more often than not, trial and error. With so many factors, however, isolating the variables (the sound) is imperative to getting to the end result faster.
A phonetically consistent treatment strategy means practicing the same thing over and over. What is practiced is consistent and does not change. The words might change, but the phoneme and its positioning is the same (say, sip, sill, soap, …). Thus, successful correction of the disorder is found in manipulating or changing the other factors involved with speech production (tongue positioning, cerebral processing, etc.). Once a successful result (speech) is achieved, then consistent practice becomes essential to reinforcing correct productions.
When the difficult sound is mastered, the child will then learn to say the sound in syllables, then words, then phrases and then sentences. When a child can speak a whole sentence without lisping, attention is then focused on making correct sounds throughout natural conversation. Towards the end of the course of therapy, the child will be taught how to monitor his or her own speech, and how to correct as necessary. Speech therapy can sometimes fix the problem, but however in some cases speech therapy fails to work.
Permanent lisps can often be corrected through extensive oral operations. Often, when a patient has extreme overbite, causing a lisp, having orthodontic braces and rubber bands for an extended period of time will correct the issue, and resolve the lisp.
- Bowen, Caroline. "Lisping - when /s/ and /z/ are hard to say". Retrieved 2006-03-07.
- Peters, Michael (2004) BMA A-Z Family Medical Encyclopedia p. 470
- Rege, Vivek. "Tongue Tie in Infants". Retrieved 14 March 2013.
- Laurie Bain Wilson (April, 1999) "Unlearning a Lisp", Parenting, 0890247X, Vol. 13, Issue 3
- Beth Morrisey MLIS (25 September 2012) "Lisps", SpeechDisorder.co.uk
- Caroline Bowen (23 November 2011) "Lisping - When /s/ and /z/ are hard to say", speech-language-therapy dot com