Lisps | speech-pathology

Li[th]sp

A lisp is a type of functional speech disorder, which is one of several speech sound disorders that can occur in children and persist into adulthood.

A child with a functional speech disorder has a difficulty, at the phonetic level, in learning to make a specific speech sound (e.g., /r/), or a few specific speech sounds, which may include some or all of these: /s/, /z/, /r/, /l/ and /th/.

"Suffering succotash!"

Severity and Prevalence

Lisps are a binary disorder. By the simplest definition, they are an inability to make certain sounds. You either can or cannot. However, functional speech disorders and phonological disorders can co-exist, so you might find a child with a phonological disorder who also lisps. In other words, and rather more technically, phonetic and phonemic speech sound deviations can co-occur in the same individual.

How can you identify the differences?

Studies have identified that anywhere from approximately 2 to 25% of young children have suffered from some form of speech disorder.

Frontal lisp
Lateral lisp
Nasal lisp
Strident lisp
Palatal lisp

Communication Disorders

Language disorder
Speech sound disorder (lisps)
Childhood-Onset Fluency Disorder (Stuttering)
Social (pragmatic) communication disorder
Unspecified communication disorder

Frontal and Lateral Lisp

Types

What causes lisping?

The cause of the disorder is unknown. But most lisps are caused by errors in tongue placement within the mouth.

Tongue thrust (tongue protrudes beyond front teeth)
Ankyloglossia or tongue-tie in children.
Over/underbites may cause non-lingual lisping.
Dental work, dental appliances (dentures or retainers or swollen or bruised tongues (temporary)
FSD is probably at a phonetic level which becomes habitual
Functional speech disorders are speech disorders, while phonological disorders are linguistic (language) disorders. What is the difference?

A frontal lisp occurs when the tongue is placed anterior of the target. 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 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 lateral lisp is where 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' 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 nasal lisp 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 of 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 later may be transcribed [s̠] and [z̠], [ʃ] and [ʒ], or the like.

Cited from:

Bowen, Caroline. "Lisping - when /s/ and /z/ are hard to say".

Encyclopedia of Children's Health

International Phonetic Alphabet (Wiki)

Age of Treatment Onset for Frontal Lisp

John Reisman (1986) Behavior Disorders in Infants, Children, and Adolescents

Interventions

Treating lisps (and other articulation disorders) mainly focus on getting sufferers to identify the patterns and mechnical skills required to successfully produce target sounds.

For a detailed description of some of these approaches, the American Speech-Language-Hearing Association has a thorough overview.