Speech sound disorders (SSD) are complex conditions which affect the ability to communicate. They range
from saying sounds incorrectly to being completely unable to speak or understand speech. A speech sound
disorder is an impairment of voice, articulation of speech sounds, and/or fluency. These deficiencies are
seen in communication and use of oral coordination.
Speech sound disorders may be separated into two primary groups, articulation disorders (also called
phonetic disorders) problems with making sounds in alphabet, and phonological disorders (also called
phonemic disorders) problems with distinctive sounds in spoken language. Speech sound disorders are
speech disorders in which some speech sounds (phonemes) are either not produced, not produced
correctly, or are mispronounced. However, some children may have a mixed disorder in which both
articulation and phonological difficulties exist. Though speech sound disorders are associated with
childhood, some effects may continue into adulthood.
Children with SSD’s make up for approximately 15% of children referred to speech and language therapy,
usually at 3 years of age. It is likely that these children represent a diverse group, excluding children with
disorders such as pervasive developmental delay, and other neurological developmental disorders.
Characteristics found in SSD:
• Omissions: Certain sounds are not produced entire syllables or specific sounds may be deleted.
• Additions: An extra sound or sounds are added to the intended word.
• Distortions: Sounds are changed slightly so that the intended sound may be recognized but sound
inaccurate or may sound like any sound in the speaker’s fluent language. The best known example of
distortion is a lisp.
• Substitutions: One or more sounds are substituted for another; e.g. twee instead of the tree.
Some distorted forms of /r/ may be mistaken for /w/ by a casual observer, yet may not actually be either
sound but somewhere in between. Further, children with severe speech sound disorders may be difficult to
understand, making it hard to recognize which word was actually intended.
The causes or origin of children with early speech sound disorders are unknown. The search for genetic
influences is difficult and has not been research thoroughly. It is likely that SSDs have more than a single set
of causes that contribute to the incidence of the disorder.
Phonological Disorders and Articulation Disorders
Both phonology and articulation refer to the structure of forming the individual sounds in speech. They do
not relate to producing or understanding the meaning or content of speech. A child with either a
phonological disorder or an articulation disorder is often difficult to understand.
The child incorrectly makes group of sounds, usually substituting earlier developing sounds for later-
developing sounds and consistently omitting sounds. Children with phonological deficits often substitute t/k
and d/g. They frequently leave out the letter s so stamp becomes tamp and snake, nake. Phonological
deficits usually seriously affect fluency. Sounds may be well articulated, but inappropriate for the context.
Diagnosis is normally made between 2 and 4 years of age. In terms of their sound structure, children with
phonological disorders produce, on average, 8 of the 24 letters in the English language. Most children
respond well to intervention, which can take several years. There is extensive research relating to
phonological disorders and difficulty with learning to read. Early intervention is important with these
children. The cause is most frequently linked to temporary hearing loss due to colds, ear infections, and
Children with severe phonological disorders present a particular medical and academic challenge. Their
accumulation of language might include nasals, stops and glides, but not at all places of verbalization and
difficulty with speech sounds produced, due to breath moving against a narrowing of the vocal tract. Some
children also have poor or errors in vowel capacity. Most notably, however, these disadvantages on the
sound system come in the absence of any other obvious deficits. These children’s prenatal and
developmental histories are typical; they have normal hearing and intelligence; other areas of the linguistic
system are intact; and they do not commonly appear to have perceptual, processing, or oral-motor
Possible Causes of Phonological Disorders
There is no known cause of phonological disorders in children. Primary and rising evidence points to
possible genetic origins for a limited number of children.
Still others have identified risk factors that increase the probability for developing the disorder as based on
male gender, an affected sibling, and low maternal education. Aside from these observations, little is else
known about the underlying cause of phonological disorders.
An important detail known is that there is a critical period for speech sound normalization. The most
favorable window of time in which to modify a child’s sound system with the target language is between the
ages of 4 and 6. Moreover, beyond age 8.5, there are level in learning, which limits the amount and degree
of change in adjustment. These, in turn, can further impact children’s ability to read, write, and perform
academically. As a result, while there is no known cause, there is a critical and early need for clinical
treatment of phonological disorders. In particular, linguistic qualities of sound systems can be used to
enhance phonological learning in treatment.
Treatment Approaches for Phonological Disorders
Minimal pairs - This approach can be used with children with moderate to severe phonological disorders
and poor speech intelligibility. In this approach, the SLP selects words which differ by only one sound to
draw the child's attention to the fact that meanings are indicated by the difference between the chosen
Phonological cycle approach - This approach uses three key elements which include auditory overload of
phonological targets at the beginning and end of sessions, to teach formation and a series of the sound
Articulation is a general term which refers to the production of individual sounds. The production of sounds
involves the coordinated movements of the lips, tongue, teeth, palate (top of the mouth) and respiratory
system (lungs). It also includes many different nerves and muscles used for speech.
When young children are growing, they develop speech sounds in a predictable order. A child with an
articulation disorder has difficulty producing and forming particular speech sounds properly (an example
'lisp') or they may not be able to produce a particular sound (for example the 'r' sound). These disorders are
generally very specific and need therapy from a trained speech pathologist.
An articulation disorder can co-occur with giftedness, language and learning disabilities, and retardation. The
causes are varied and may be linked to temporary hearing loss due to otitis media (frequent ear infections) or
allergies; structural or functional problems with the lips, teeth, tongue, or hard palate; or a medical condition
such as cleft palate or cerebral palsy.
Articulation errors are characterized by the omission, distortion, substitution, addition and/or incorrect
sequencing of speech sounds.
Causes of articulation disorders:
• Hearing Loss
• History of ear infections during the first few years of life
• Speech sound perception and ability to distinguish
• Tooth alignment and missing teeth
• Impaired oral-motor skills
• Eating problems
• Tongue thrust swallow after 6 years of age
• Neurological disorders
• Mental retardation
• Language problems
• Reading disorders
• Family history
Articulation Assessment / Articulation Test
Formal assessment should include both articulation and phonology. A speech-language pathologist (SLP)
should use caution in the interpretation of standardized scores to determine need for service. Although some
assessments will reveal standardized scores below the average range for single sound inaccuracy, services
may not be necessary if there is not a poor educational outcome. The standardized scores should be
interpreted carefully, always taking into consideration impact on educational performance.
A speech-language pathologist is the professional that evaluates children with speech and language
difficulties. The SLP listens to the child and may use a formal articulation test to record sound errors. An
oral mechanism examination is also done to determine whether the muscles of the mouth are working
correctly. The SLP may recommend speech treatment if the sound is not appropriate for the child's age or if
it is not a trait of jargon or accent. For all children, the SLP often also evaluates their language development
to determine overall communication functioning.