Finding Order in Disorder: Relational and Independent Speech Sound Disorder Analysis

Did you know that speech sound disorders (SSD) are the most prevalent communication disorder?

According to Dodd, of the five different types of described speech sound disorders, two types, phonological delay and consistent deviant phonological disorder, comprise 77% of all SSD. These disorders are rule governed with predictable and systemic error patterns, and they can range in severity from mild to severe.

Children who are highly unintelligible present a challenge when it comes to identifying their predominant error patterns. As many parents have said, it’s as if these children have a language of their own!

Models of Analysis

Fortunately, multiple models of analysis are available to help SLPs analyze moderate to severe SSD, which leads to more effective intervention planning. The models fall under different analysis frameworks, and clinicians can select the most appropriate one to use based on the nature and severity of the SSD.

These analysis models provide SLPs with the tools needed to act as “linguistic detectives” and find the order in the disorder of these complex sound systems.

Relational Analyses

The oldest and most common type of analysis, relational analyses have been used by SLPs since the beginning of the profession. Several different analyses fall under this category, including:

  • Substitution, omission, distortion, and addition analysis (SODA)
  • Phonological process analysis (PPA)
  • Place-voice-manner analysis (PVM)

While there are differences across these different relational analyses, they all share some similarities:

  • They compare the child’s pronunciation to an adult target.
  • They only examine errors, making them specifically “error analyses.”
  • They make sound-to-sound comparisons between child and adult forms.
  • They use a pre-determined and finite number of categories or rules to describe the child’s errors.

Independent Analyses

Independent analyses are newer and less commonly used methods to describe children’s disordered sound systems. Like relational analyses, several different independent analysis methods are available, including:

  • Systemic phonological analysis of child speech (SPACS)
  • Productive phonological analysis (PPK)
  • Non-linear phonological analyses, such as optimality theory (OT)

Again, these analyses share a number of common features:

  • They describe the sound types (phonetic inventory) and syllable structures produced by the child independent of the adult target.
  • They identify what the child does rather than what the child does not do.
  • They compare child sound system to adult sound system; in other words, they are system-to-system comparisons.

The first independent analyses were used to describe early, developing sound systems in children under the age of 3 who had not developed a rule-based sound system. However, in the SPACS, PPL, and OT, independent analysis is used as a first step in describing the rule-governed sound systems of children ages 3 and over who do have rule-based sound systems.

Once the child’s sound system has been described as a unique, self-contained sound system through independent analysis, it is then necessary to compare it to the adult system to determine the areas of difference, or disorder, so the clinician can plan intervention. This is done through relational analysis. This means that SPACS, PPL, and OT combine both independent and relational analysis methods.

Over the next three articles of this four-part series, both the PVM and the SPACS analyses will be looked at more closely. Finally, the concepts will all be put together in a discussion about choosing an appropriate analysis method for the case at hand. Be sure to stay tuned!

  1.  Dodd, B. (2005). Differential Diagnosis and Treatment of Children with Speech Disorder. London: Whurr.
  2. Skahan, S., Watson, M., & Lof, G. (2007). Speech-language pathologists’ assessment practices for children with suspected speech sound disorders; Results of a national survey. AJSLP, 16, 246-259.
  3. Williams, A. L. (2001). Phonological assessment of child speech. In D. M. Ruscello (Ed.), Tests and Measurements in Speech-Language Pathology (pp. 31–76).  Woburn, MA: Butterworth-Heinemann.
  4. Williams, A. L. (2005). Assessment, target selection, and intervention: dynamic interactions within a systemic perspective. Topics in Language Disorders, (25)3, 231-242.
  5. Williams, A.  L. (2006). A systemic perspective for assessment and intervention: a case study. International Journal of Speech-Language Pathology, 8, 245-256.
  6. Williams, A. L. (2015). Assessment and intervention from a systemic perspective. In C. Bowen (2nd edition), Children's Speech Sound Disorders (pp. 199-203). Oxford: Wiley-Blackwell.