Speech and language impairment affects a median of 5.95% of children. Particular factors are known to place children at greater risk of delay including low gestational age and birthweight. Although a proportion of neonates in these increased risk groups develop age-appropriate communication skills, others may demonstrate significant difficulties that have been shown to detrimentally impact on social and educational outcomes.

1. 
   

   Language

   
   
   
   
   1. 
      

      Refers to the “complex and dynamic system of conventional symbols that is used in various modes for thought and communication.”

      
      
   2. 
      

      It is a rule-based system that can be divided into five domains.

      
      
      
      
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        Phonology

        
        
      • 
        

        Morphology

        
        
      • 
        

        Syntax

        
        
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        Semantics

        
        
      • 
        

        Pragmatics

   
   
2. 
   

   Speech

   
   
   
   
   1. 
      

      Defined as the articulation of speech sounds to convey language

      
      
   2. 
      

      Achieved through the coordination of several systems

      
      
      
      
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        Respiratory

        
        
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        Phonatory

        
        
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        Laryngeal

        
        
      • 
        

        Velopharyngeal

   
   
3. 
   

   The development of speech and language is highly complex, but the majority of children attain these functions with relative ease. Table 46-1 summarizes normal speech and language development during childhood, although it is important to emphasize that variability exists in the timing of these milestones.

   
   
   
   
   1. 
      

      Precursors of speech and language

      
      
      
      
      1. 
         

         Develop in the first year of life.

         
         
      2. 
         

         Up to 9 months of age, children are “preintentional communicators” whereby their actions are not produced with an intended purpose.

         
         
      3. 
         

         Children’s speech-motor control progresses from vowel-like sounds (with the articulators at rest) to the formation of well-formed and timed syllables.

         
         
      4. 
         

         This form of babbling, known as canonical, precedes a child’s first word, which typically occurs around 1 year of age.

      
      
   2. 
      

      First words

      
      
      
      
      1. 
         

         Typically consist of nouns, with verbs and adjectives appearing around 20 months.

         
         
      2. 
         

         By 17 months of age, approximately 50% of children demonstrate a vocabulary of 50 words.

         
         
      3. 
         

         Between 18 and 20 months, most children have experienced a rapid burst in vocabulary development and are beginning to produce two-word utterances.

         
         
      4. 
         

         At 3 years of age, infants are able to form simple sentences consisting of three or more words that incorporate basic syntactic structures and grammatical markers.

         
         
      5. 
         

         By age 5, children have acquired all the morphological markers of the English language, and are able to use a variety of simple and complex sentence types.

      
      
   3. 
      

      Beginnings of speech development

      
      
      
      
      1. 
         

         Children typically acquire sounds in an orderly sequence.

         
         
      2. 
         

         There are a variety of speech classification systems proposed, with an enduring model being Shriberg’s grouping of consonants according to their approximate order of acquisition (the “early-, middle-, and late-8”).

         
         
         
         
         • 
           

           The “early-8” sounds consist of m, b, j (as in yes), n, w, d, p, h.

           
           
         • 
           

           Followed by: t, ŋ (as in ring), k, g, f, v, ʧ (as in chair), ʤ (as in bridge) (the “middle-8”).

           
           
         • 
           

           Followed by: ʃ (as in she), θ (as in thumb), s, z, ð (as in this), l, ɹ (as red), ʒ (as in measure) (the “late-8”).

         
         
      3. 
         

         By 4 years of age, the majority of these sounds should be produced correctly and there is a considerable decline in the occurrence of phonological errors. At this age, a child’s speech should be fully intelligible to strangers.

         
         
      4. 
         

         Any residual phonological error patterns should be eliminated by 6 years, but some children may continue to demonstrate difficulty with some of the late-8 sounds (ie, /θ, ð, ɹ/).

         
         
      5. 
         

         By 8 years of age speech-sound acquisition should be complete.

An understanding of typical speech and language development is essential for diagnosing any aberrations from the typical developmental trajectory. A comprehensive assessment involves obtaining a thorough case history, identifying any medical, developmental, or environmental factors that may potentially be impacting on speech and language development (such as hearing impairment, cognitive delay, comorbid developmental disorders such as attention deficit hyperactivity disorder, etc), and assessing children’s speech and language abilities using standardized measures. Commonly used assessment methods are described below and details of language and speech tests are provided in Tables 46-2 and 46-3, respectively.

1. 
   

   Language assessment

   
   
   
   
   1. 
      

      During the prelinguistic phase of development (9 to 18 months) assessment of language involves determining whether a child is able to communicate intentionally.

      
      
   2. 
      

      Between 18 and 24 months of age, the focus is on determining a child’s rate and range of communication functions, the use of words rather than gestures and their receptive language abilities.

      
      

      The above areas are often measured during play-based assessments (eg, Communication and Symbolic Behavior Scales—Developmental Profile [CSBS-DP] or through parent-report measures. Standardized parent-report measures include the MacArthur-Bates Communicative Development Inventories (CDI) and the Caregiver Questionnaire of the CSBS-DP.

      
      
   3. 
      

      Between the ages 2 and 4 years is often difficult; however, some children may respond well to toy-based instruments such as the Preschool Language Scale—5 (PLS-5) and the New Reynell Developmental Language Scales. During this period, conversational speech samples are often used to assess semantic and syntactic development using analyses such as Mean Length of Utterance, Developmental Sentence Score, and Type-Token Ratio.

      
      
   4. 
      

      At later ages, a variety of standardized language assessments are available to measure different language abilities (pragmatics/social skills, semantic, or grammatical development) in both receptive and expressive language domains. The choice of language measure will depend on a range of variables such as the child’s age and cognition, the language domains of interest and whether any comorbid motor, hearing, or vision impairments will impact on the child’s ability to respond to tasks.

   
   
2. 
   

   Speech assessment

   
   
   
   
   1. 
      

      Speech examination should always begin with evaluation of the structure and function of the oral musculature. Without this information, it will be impossible to provide an accurate diagnosis of the child’s speech sound disorder.

      
      
   2. 
      

      The assessment should then include testing of both articulation (the child’s ability to actually produce the sound at a motoric level) and phonology (the child’s understanding of the speech sounds of their language). A differential diagnosis between articulation and phonological disorders is critical to ensure that therapy is targeted at the correct domain (ie, targeted at the child’s motoric production of the sound where an articulation disorder is present, or at the child’s underlying representation of the sound where a phonological disorder is present).

      
      
   3. 
      

      Conversational samples are more representative of a child’s typical speech profile.

      
      
      
      
      1. 
         

         It is recommended that a standard clinical assessment should obtain both single-word and connected speech samples.

         
         
      2. 
         

         In addition to providing a more functional representation of speech production, conversational speech samples also allow for the assessment of other important speech elements such as

         
         
         
         
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           Voice

           
           
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           Prosody

           
           
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           Fluency

           
           
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           Intelligibility

      
      
   4. 
      

      Widely used measures of articulation and phonology are detailed in Table 46-3

      
      
      
      
      1. 
         

         Goldman-Fristoe Test of Articulation-2 (GFTA-2): The GFTA-2 yields a standard score with separate norms provided for males and females. One disadvantage of the GFTA-2 is that it does not assess phonology, although it can be used in conjunction with the Khan-Lewis Phonological Analysis.

         
         
      2. 
         

         Diagnostic Evaluation of Articulation and Phonology (DEAP), which measures articulation and phonology as well as oromotor function and the stability of a child’s phonological system.

      
      
   5. 
      

      Stimulability of absent speech sounds should be determined. Stimulability involves testing whether a child can produce a misarticulated sound when provided with maximum auditory, visual, and tactile cues.

      
      
   6. 
      

      Speech musculature should be assessed to determine whether abnormal oromotor functioning is impacting on sound production. The Verbal Motor Production Assessment for Children has been found to be the most psychometrically robust assessment of oromotor functioning in children. The VMPAC assesses the neuromotor integrity of the motor speech system in children aged between 3 and 12 years and assists in the diagnosis of motor speech disorders, including dysarthria and apraxia of speech, as well as more subtle neuromotor impairments.