What’s in a Name? Does SSD Smell Sweeter than DPD?

Francoise and I are engaged in the writing of two books currently. I am taking the lead on the revision (mostly cosmetic) of Developmental Phonological Disorders: Foundations of Clinical Practice (the “big book” that we call DPD for short) while Francoise is taking the lead on the writing of a new undergraduate text that will prepare readers to tackle the “big book” at the graduate level or to use the DPD text as a handbook in clinical practice. We still haven’t figured out what to call the second book! Introduction to Speech Sound Disorders? Introduction to Developmental Phonological Disorders? Introduction to Articulation and Phonological Disorders? Some combination of the above? We notice that many of the undergraduate text books now have very long titles because the authors keep adding terms as they become “fashionable”. I have just arrived (in my revising) at the introduction to Part II of the DPD text in which we explain our preference for the term Developmental Phonological Disorders. Even though this text is copyrighted to Plural Publishing Ltd. I am going to reproduce it here in case any of my readers would like to weigh in. We have been told that instructors cannot use the big DPD text because it is not titled with the preferred American term ‘speech sound disorders’ and I have met readers who were very surprised to learn that we covered articulation disorders and motor speech disorders in the book, as if the children with these problems did not have developing phonological systems! So much complexity here – I look forward to your thoughts in the comments or on twitter or by email. Here is the text from our book, Part II Introduction:

Developmental Phonological Disorders as the Diagnostic Term

As we discuss the application of the ICF framework in the context of DPD, we must be begin by unpacking the term “developmental phonological disorder” and justifying this choice of terminology to describe this health condition. Since the dawn of our profession, many terms have been used to describe children who have unintelligible or inaccurate speech, with all of the terms reflecting the tongue-in-cheek perspective of Compton (1970) who compared the diagnostic role of the SLP to that of a “TV repairman”! The diagnostic term that is applied specifies the “part” that is presumed to need fixing, either “articulation,” “phonology,” or “speech,” with these terms all in current use although, historically, earlier usages focused on articulation problems and current preference in North America is to refer to “speech” as a cover term that is presumed to include both the articulatory and phonological aspects of the child’s difficulty. We feel, however, that “speech” is too broad a term because it is often used as a cover term for difficulties with articulation, stuttering and voice in epidemiological studies, as seen in Chapter 7. Furthermore, in the developmental context there is no possibility of separating articulation from other aspects of phonological knowledge. Children who appear to have a motor speech problem called childhood apraxia of speech have significant difficulties with various aspects of phonological processing (see Chapter 7 for further discussion of this point). Returning to the topic of cleft lip and/or palate, this structural disorder that might appear at first glance to cause a purely articulatory problem, actually results in speech patterns that are best described and treated with phonological approaches (Howard, 1993; Pamplona, Ysunza, & Espinoza, 1999). Therefore, it is our preference to identify the central issue as being in the child’s developing phonological system, stressing as we do throughout this book, that phonology comprises interlocking components at multiple levels of representation.

The diagnostic term also requires one or more modifiers that indicate a specific type of phonological problem. We use the term “developmental” to simply denote that we are referring to children whose phonological systems are still developing. Furthermore, as shown in Chapter 7, the most likely causal factors in the majority of cases are interacting genetic and environmental variables that impact primary neurodevelopmental processes. The modifier “functional” was used for many decades, sometimes replaced with the phrase “of unknown origin,” to differentiate problems that had a known biological cause from those that did not and were therefore presumed to reflect an unexplained failure to learn the required articulatory gestures or an unexplained delay in the suppression of phonological processes. We reject these terms on the grounds that distinguishing between biological causes that are currently known and those yet to be discovered is nonsensical and that, furthermore, we cannot force a pure demarcation between biological and environmental causes. For example, so-called functional speech problems are indeed associated with sociodemographic disadvantages (for discussion, see Shriberg, Tomblin, & McSweeny, 1999) but these sociodemographic conditions are themselves associated with biological causal-correlates such as increased risk of otitis media, fetal and child exposure to parental smoking, and low birth weight. Furthermore, environmental variables and biological maturation are reciprocally related as discussed in Part I: maturation of brain function in areas associated with language and reading development is driven in part by exposure to high quality language input. In another example, Noble, Wolmetz, Ochs, Farah, and McCandliss (2006) demonstrated that socioeconomic status significantly moderates the relationship between brain function and phonological processing even when phonological abilities are controlled across advantaged and disadvantaged groups. The nature of the relationship is such that high quality inputs for children in advantaged homes buffers them from the ill effects of poor phonological processing abilities, allowing them to achieve higher reading levels and higher activations in areas of the brain important to reading than would be predicted on the basis of their phonological processing abilities alone. Disadvantaged children show a correspondence between brain activation and reading ability that is linearly predicted by their phonological processing skills, however. These kinds of studies support a dynamic systems approach to phonological disorders and highlight the joint causal influences of intrinsic and extrinsic factors on children’s linguistic functioning (issues that are revisited in Chapter 7 when we discuss approaches to the subtyping of phonological disorders). For these reasons we prefer the modifier “developmental” rather than “functional” or any other term that strictly demarcates biological and nonbiological causes of phonological difficulties.

Finally, there continues to be some controversy about whether the problem should be referred to as a “disorder” or a “delay.” In fact, as we discuss further in Chapter 7, some classification systems explicitly differentiate between children whose speech appears to be delayed by virtue of having characteristics similar to younger normally developing children and those whose speech has characteristics deemed to be atypical. We argue as we move through Part II that the diagnostic and prognostic implications of this distinction are uncertain and that the delay-disorder classification exists more on a continuum of severity than a sharply delineated categorical distinction. With respect to those children who are deemed to have a “disorder” on the basis of “atypical” speech errors or learning processes, it is our impression that the child’s behaviors are only “atypical” in the context of the child’s age or overall profile. For example, inconsistent word productions are often considered to be atypical and yet we showed in Chapter 4 that variable word productions are fully expected in the earliest stages of word learning. Therefore atypical behaviors reflect heterochronicity in developmental trajectories across cognitive-linguistic domains within a child rather than fundamentally different learning processes across children. As to those children who appear to have typical but delayed patterns of speech error, we take the position that some children’s delay is severe enough that it places them at risk for current or future activity limitations and participation restrictions. Consistent with the position of the ICF-CY (McLeod & Threats, 2008), the problem in this case deserves the appellation “disorder”. Furthermore, to be consistent with the dictionary definition of the word “disorder”, this appellation justifies an intervention to change the child’s rate or course of development so as to synchronize function among different developmental domains or to align function with expectations for activities and participation.

Ultimately, this brings us to the diagnostic term developmental phonological disorder (DPD), which corresponds to one of the superordinate categories in the Speech Disorders Classification System as originally formulated (Shriberg, Austin, Lewis, McSweeny, & Wilson, 1997). DPD can be contrasted with normal (or normalized) speech acquisition, differentiating those children whose speech development is progressing as expected from those children who, at ages younger than 9 years, are producing more speech errors than would be expected for their age. Nondevelopmental phonological disorders denotes those cases where the speech difficulty has its onset after 9 years of age. Speech differences arise from cultural and linguistic diversity and are not considered to be a speech impairment (although a speech difference may overlap with a coexisting health problem and may have functional consequences for an individual’s participation in some environments). The outcome of the initial assessment of a child who is referred due to concerns regarding speech accuracy or intelligibility should be a diagnosis with respect to one of these 4 major categories. Subsequent to an initial diagnosis of DPD the SLP may also diagnose a specific subtype of DPD, as discussed in Chapter 7.

We point out here that throughout Parts II and III we remain focused on those cases where the child’s primary difficulty is with speech (and/or language and/or reading). We do not specifically cover secondary phonological disorders in which the child’s speech delay is directly associated with impairments of sensory systems, cognitive deficits, craniofacial anomalies or other developmental disorders. The assessment and treatment procedures to be described are applicable to children with secondary speech delay with modifications to take these specific developmental conditions into account however.


Compton, A. J. (1970). Generative studies of children’s phonological disorders. Journal of Speech and Hearing Disorders, 35(4), 315–339.

Howard, S. J. (1993). Articulatory constraints on a phonological system: A case study of cleft palate speech. Clinical Linguistics and Phonetics, 7, 299–317.

McLeod, S., & Threats, T. T. (2008). The ICF-CY and children with communication disabilities. International Journal of Speech-Language Pathology, 10, 92–109.

Noble, K. G., Wolmetz, M. E., Ochs, L. G., Farah, M. J., & McCandliss, B. (2006). Brain-behavior relationships in reading acquisition are modulated by socioeconomic factors. Developmental Science, 9, 642–654.

Pamplona, M. C., Ysunza, A., & Espinoza, J. (1999). A comparative trial of two modalities of speech intervention for compensatory articulation in cleft palate children: Phonological approach versus articulatory approach. International Journal of Pediatric Otorhinolaryngology, 49, 21–26.

Shriberg, L. D., Austin, D., Lewis, B. A., McSweeny, J. L., & Wilson, D. L. (1997). The Speech Disorders Classification System (SDCS): Extensions and lifespan reference data. Journal of Speech, Language, and Hearing Research, 40(4), 723–740.

Shriberg, L. D., Tomblin, J. B., & McSweeny, J. L. (1999). Prevalence of speech delay in 6-year-old children and comorbidity with language impairment. Journal of Speech, Language, and Hearing Research, 42(6), 1461–1481.

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  1. Very well-written blog, as usual. If I were required by the language police to choose between SSD and DPD (rather than our even broader preferred term, protracted phonological development), I would choose developmental phonological disorders for the well-articulated reasons above and for another reason. The speech “SOUND” disorder label focuses attention on the speech SOUND, rather than other human bodily sounds or the entire phonological hierarchy. Decades of work in SLP have demonstrated the importance of considering the entire phonological hierarchy and associated domains. Under the umbrella term, we can focus in on areas within or related to the phonological system that are affecting a particular individual, which could even, dare I say publicly, encompass so-called motor ‘planning’ for speech production (include sCAS too under the DPD umbrella? How radical!).

    Footnote 1: Restricting what students read because of textbook titles…Words like ‘censorship’, ‘dogmatism’, rigid adherence to sameness (DSMV) come to mind.

    (Footnote 2- Note that our term, “protracted phonological development”, has the same assessment and therapeutic intent t as DPD. Protracted is not simply ‘delayed’ and includes a ray of hope while not guaranteeing normalization – The word ‘disorder’ is missing on purpose – acknowledging that all people on the bell curve are in the fold – but I digress – a discussion for another day).

    • Thank you for your reply, thoughtful and a helpful contribution as always. I totally agree about the language police! And the importance of considering the full phonological hierarchy in all cases, which is the part I like about your term “protracted phonological development”. The difficulty I have is that it seems to me that it applies to everyone, we all have protracted phonological development since it is a lengthy developmental process for everyone. The issue for the SLP and the client/family is to decide when it has become so protracted that an intervention is warranted. I do not find “disordered” to be a sinister term, it simply means that something is out of place. Once this has been acknowledged you can decide to leave it where it is because you like it there, or find a way to work around it even though it is a bit of a nuisance or you can try to get it back where it belongs. This is the client’s choice. In no way does it imply hopelessness. Even in cases like my daughter’s autism where she has no “hope” and no desire to be neurotypical she acknowledges the need of extra supports to achieve the goals that all young people have. She finds the diagnosis to be a source of community and an access point to needed services, not an indication that there is no hope.

      • It is true we do all have protracted development on all fronts…and it is also my perspective that there are many reasons to seek and receive help or not – while we are on this journey called life with whatever our genetics and environment gave or didn’t give us. We are unlikely to change our perspective on the word ‘disorder’ which I find dis-tasteful but I still would choose DPD over SSD always for your book title and support you in that. Off to Greece for a conference now!!

      • Thank you for your reply and for validating our use of “phonological” I respect your feelings about “disorder” – there are two diametrically opposed senses about a whole host of terms, normal, handicap and so on, where there are good points on both sides. Have fun in Greece.

  2. Another comment – the language police cannot be that concerned with Greek and Latin root words like ‘phonology’ because they are fond of words like ‘apraxia’, ‘aphasia’, ‘dysphagia’ etc

  3. Marie-Pier Gingras

     /  September 7, 2015

    It may be because I am so use to the expression “trouble phonologique” in French, but DPD sounds perfect to me. I also feel that “speech disorder” is too broad and emphasis the articulation problem rather than the whole phonological system. I also agree with the “disorder” term. I think it reflects what is going on and the need for intervention. Which can have good outcomes ! For French-SLP, “trouble phonologique” and “dyspraxie” are view as two populations. It would not have been automatic for me to include CAS in DPD, but I fully understand why.

    On the same “what expression is best” reflexion, since a couple of months, I have been debating delay vs. disorder vs difficulty. Recently, I have dropped the “delay” expression (“retard” in French) because it kinds of “predict” that the child will recover completely before school (and that, I can’t predict!). I use “language difficulties” or “language disorder”. I personally find some SLP are looking for “reasons” to excuse language difficulties of children, whether it is ear infections, poor stimulation, inattention of the child, etc. They then don’t use the word “disorder” because language difficulties “may have been causes/influences” by something else. But, this is another subject =)

    • Thank you for your comments, I am still getting used to the strict division between delay and disorder in Quebec with the implications for receipt of services. I think that there are cases in which apraxia is a completely separate disorder from DPD and others where it emerges as a very severe form of DPD so we do discuss it quite a bit in our book.


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