This review was updated from the original version in August 2022. We made a correction to the research linked under the complexity approach.

Speech sound disorders. It’s one of those things our relatives who don’t really understand what we do assume is the only thing we do. It’s one of the areas of practice our field was founded on, and one where we’re fortunate to have an array of treatment approaches (like, dozens) backed up by decades of research, for both phonological and articulation disorders. All these evidence-based options can be a challenge to navigate, though, and choosing the right approach could mean the difference between a child meeting their goals and “graduating” from speech and that same child staying on the caseload for years. That’s exactly why we’ve put together this Ask TISLP: to give you a starting point for making informed treatment decisions. To narrow things down, we’ll be focusing only on idiopathic (traditionally called “functional”) SSDs—those rooted in articulation and/or phonology and without a known cause. That means that we’re not talking motor speech (CAS & dysarthria), or speech disorders related to cleft/craniofacial conditions or to hearing differences. But never fear! You can search all of those topics using the filters in our database to find reviews on supporting speech for those kiddos. 

Here’s what to expect: 

1. A quick review of the difference between articulation-based and phonologically-based SSDs
2. But wait. Is there even a difference? Paradigm shift!
3. A rundown of the major treatment approaches and their evidence bases
4. Your lingering questions, plus resources for digging deeper

Before you ask—yes, there’s a cheat sheet. Grab our downloadable chart of treatment approaches here, but don’t skip the discussion, ok? Context matters. Let’s get this party started!

Articulation versus phonology and why it matters

We make a distinction between articulation and phonologically based errors because we need to address them differently and because the phonology side of things has had a tendency to get overlooked. 

Articulation errors are motor-based—there’s a breakdown in the movement of the articulators, so our therapy for articulation errors focuses on accurate placement and movement of the tongue, lips, teeth, etc. 

Phonological errors, on the other hand, are language-based, meaning that the child has incorrect or fuzzy mental representations of the speech sounds. Let’s break that one down a bit. When we learn the phonology of a language, our brains learn the rules for which qualities of sounds are phonemic and important for meaning (like the final voicing difference in /bæk/ vs /bæg/), and which aren’t. For example, the aspirated /p/ in “pin” and the unaspirated one in “spin” both fit in our same mental category of English /p/—although the same wouldn’t be true for every language! A child with phonological errors may have internalized the “wrong” rules—like disregarding the manner difference between /s/ and /t/ and storing them in the same mental category. This might surface as a consistent stopping error. Fuzzy phonological representations happen when kids are still learning to make sense of the rules, like the fact that fricatives are long and noisy and stops are short, so they aren’t able to clearly and consistently distinguish fricatives from stops. This might show up as inconsistent errors. When you start looking, phonology is everywhere: even single-sound errors might show up phonologically in a child’s decoding and spelling. Therefore, phonological therapy needs to help the child internalize the correct phonological rules.  

Of course, in a lot of cases, articulation and phonological issues are both in the mix. Kids that have both types of errors have incorrect/fuzzy representations stored in their brains AND make motor mistakes. For example, a child who glides liquids might not have /l/ and /w/ clearly stored as different phonemes in their brain—a phonological error—AND might also not be able to move the tongue tip to the alveolar ridge to produce /l/—the articulation error. 

This all means that we need to collect sufficient data in a comprehensive assessment process to find these phonological issues when they exist. You can use formal assessments (like the HAPP-3, the DEAP, or the KLPA-3), speech sampling, and/or speech perception and phonological processing tasks like those described here to help you figure out if a child's errors are articulation-based, phonological, or both, and to identify any phonological patterns in the child’s errors. For an overview of comprehensive evaluations of children’s speech production, check out this open-access tutorial, this one for multilingual children, or this one for single speech sound errors. 

After collecting all that excellent assessment data, you’ll choose the best match of a treatment approach and go from there, keeping in mind that you sometimes might have to start therapy before totally “figuring out” the child’s working speech sound system and exactly where all the breakdowns are. That’s where clinical data collection comes in!

Articulation vs. phonology and why it maybe doesn’t matter

At a certain point, the artic/phono dichotomy outstays its welcome. We’ll let Dr. Kelly Farquharson explain:

“Fey (1992) noted that articulation and phonology are “inextricable constructs.” That is—it’s REALLY hard to separate them into black and white, stand-alone categories. Pennington (2006) actually refers to the terms “articulation disorder” and “phonological disorder” as what speech sound disorders were formerly called. As in, he assumed that we’ve moved beyond that dichotomy a long time ago. His point, also, is that if we dichotomize it, we are making assumptions about the underlying issue that we simply can’t prove—said differently, how do we prove that phonological representations are “fuzzy”? In this paper I share a few case examples of children whose speech sound production might make you assume one diagnosis, but further data suggests otherwise. One child has a single sound error—which might make one assume an articulation disorder. However, his single sound error appeared in his spelling, which speaks to fuzzy representations. The inverse was true for the child with multiple sound patterns—he might appear phonological on the surface, but his phonological skills were intact otherwise.”

Let’s think of articulation and phonology as two different lenses for looking at a child’s speech sound errors—and for assessment and treatment, we need to be wearing bifocals. 

We’ve sectioned our discussion of treatment approaches by which lens they’re based on, but don’t let that trick you into seeing your clinical decisions as an either/or situation (more on that later). 

A note on the evidence for the speech sound disorder treatment

As we take you through the different approaches, we’ll briefly address the size and quality of the evidence base for each. We got a lot of this information from this 2021 textbook edited by Williams, McLeod, & McCauley, which is an excellent resource—nerd-out kind of reading—if you want to dive deeper. Overall, most of the evidence base for idiopathic SSD treatment is based on case studies or controlled case/cohort studies (level 2 or 3 evidence, if you use the SIGNS evidence grading system). There are some level 1 randomized controlled trials (RCTs), but they’re few and far in between. This makes sense, since even though RCTs are the “gold standard,” they’re difficult, time-consuming, and expensive to carry out. So while the evidence base here is much larger and more informative than in some other areas of SLP practice, it’s certainly not perfect. As always, it's important that we use our knowledge and experience to integrate the existing evidence, keeping in mind the needs of our clients/students and their families. 

Lens #1: Articulation-based approaches 

We’ll start with an old friend: the Traditional Articulation approach, with credit to Van Riper all the way back in 1939. It was developed for children with mild articulation errors and later adapted for children with moderate-to-severe errors. 

• The rundown: Targets are (typically) addressed in a developmental progression, tackling one sound at a time until mastery. Therapy follows a production hierarchy (isolation, syllables, words, phrases, sentences, conversation) and uses elicitation strategies like imitation, placement cues, and successive approximations. The frequency and duration of therapy sessions can vary widely based on the practice setting and the child’s individual needs.
• The research: This is by far the best-researched therapy approach we’ll be talking about here, simply because of how long it’s been around and its centrality to the profession, historically. We know of 70 studies (mostly with small samples, but including 14 RCTs) that provide evidence for the Traditional approach, compared to a handful that found it less effective and efficient than phonological approaches—which makes sense for kids with phonological errors! 
• The resources: You can find a thorough description of the approach in this textbook. For elicitation strategies, Secord et al. and Caroline Bowen are excellent resources, among others.

Now chances are, this is one approach you’ve got down cold. Brumbaugh and Smit (we reviewed it here) found that SLPs supporting preschoolers with SSDs use the Traditional approach most frequently (and were less familiar with phonological approaches), and Cabbage and colleagues found it made the top three approaches among school-based SLPs, too. Remember, though, that the Traditional Articulation approach is unlikely to be efficient or effective for children with phonological errors, so don’t stop here! 

Though we’ve seen some variations in the last 80-odd years, the key components of Traditional articulation therapy remain the same. It may have a bit of auditory perception tied in—like asking if the sounds /g/ and /d/ or the words “gate” and “date” are the same or different—but it always mostly targets motor production. Research on motor learning principles tells us that distributed, variable practice on a large number of complex targets is more advantageous compared to mass practice on a smaller number of simple targets (to refresh your memory on motor learning principles, see Tables 1 and 2 of this paper). You can also use a horizontal approach to target attack to improve efficiency. Some modern spins to articulation therapy include using a computer program (like SATPAC, discussed in this review) or biofeedback (see here, here, and here to learn more), both of which are especially useful options for older children who have residual distortions on sounds like /ɹ/. 

The Stimulability Approach from Dr. Adele Miccio is another (short-term) option for addressing articulation in very young children (2–4 years old) who have extremely small phonetic inventories and are not yet stimulable for most consonant sounds. After stimulability improves, you can reassess and transition to a different approach as needed. 

• The rundown: Therapy focuses on stimulability and increasing the child’s phonetic inventory by reviewing sound character cards and corresponding hand motions (e.g., Coughing Cow, where you place your hand on your throat) and completing turn-taking play activities.
• The research: Supported by nine studies including one RCT. Studies in the evidence base describe 45–50-minute sessions once or twice a week for no longer than 12 weeks.
• The resources: This open-access paper describes the approach, and the sound character cards are freely available here.

Lens #2: Phonological approaches

We have a few more choices under this lens, and it’s critical to choose carefully based on the number, type(s), and consistency of phonological errors. Remember that we’re not focusing only on the movement of the articulators here. Phonological approaches also need to address the fact that errors like producing “toe” for “so” result in differences in meaning. We put these approaches in bullet points for readability, but remember we also have the printable chart version here for easy scanning.

Complexity Approach: For young children with phonological speech sound errors 

• The rundown: Target selection principle (described here) prioritizing later-developing sounds and clusters to create broad changes in the child’s speech sound system. Can combine with other phonological approaches—e.g., see Maximal Oppositions below.
• The research: Supported by at least 14 studies, but with some contradictory findings (see here and here).
• The resources: Dr. Holly Storkel’s 2018 tutorial is your go-to resource for selecting targets using the complexity approach. You can also find lots of resources at SLPath.com (free registration needed).

Cycles: For kids with multiple phonological errors who are highly unintelligible

• The rundown: A highly specified approach, with set rules for target selection and ordering. Therapy follows a set routine (including auditory bombardment, multiple production activities, stimulability probes, and a phonological awareness activity), addressing one error pattern at a time in a cyclical fashion with the goal of improving intelligibility overall. It may be a good choice for kids with cognitive delays or those who are frustrated with slow progress.
• Therapy intensity: 60 minutes/weekly divided among  1–3 sessions. One cycle lasts for 5–16 weeks. Complete 3–4 cycles (or 30–40 hours of therapy) to maximize results
• The research: Supported by at least 19 studies (2 RCTs, see here and here).
• The resources: See this book chapter from Prezas & Hodson (the creator of Cycles) for a detailed description of the approach. You can also check out the Cycles Handbook for clinicians from clinicians Amy Graham and Rebecca Reinking.

Core Vocabulary Approach: For kids with inconsistent phonological errors

• The rundown: Choose a pool of 70 target words in collaboration with the child, parents, and teachers. Target 10 words every session, focusing on consistency of the child’s best production (using drill-based activities to facilitate this), rather than perfect production. Remove target words from the pool when the child can produce them consistently.
• Therapy intensity: Typically, two 30-minute sessions per week for 8 weeks, but 1 or 3 sessions a week may also be effective.
• The research: Supported by at least nine studies (including an RCT described in this text).
• The resources: Check out this open-access article from Dodd et al. for a description of the approach.

Minimal Pairs: For kids with mild-moderate, consistent phonological errors 

• The rundown: Contrasts a known and unknown sound differing by one distinctive feature (e.g.,  coat vs. goat). Intervention includes familiarization, perception training, imitation, and independent production in drill–play activities.
• Therapy intensity: Typically two 30–45-minute sessions per week with a goal of 100+ trials per session. Frequency varies in the literature from more frequent (up to 5x/week) to less frequent (biweekly) sessions.
• The research: Supported by at least 41 studies (2 RCTs, see here and here). Six other studies found multiple oppositions to be more effective, which makes sense if we try to use minimal pairs (designed for kids with mild-moderate SSDs) with a child with a more severe SSD.
• The resources: The Minimal Pairs Handbook for clinicians from Adventures in Speech Pathology.

Maximal Oppositions: For kids with consistent phonological errors who are missing 6+ phonemes in their speech sound inventory

• The rundown: A complexity approach similar to minimal pairs, except the known and unknown sounds differ by multiple distinctive features (e.g. meet vs. feet; /m/ and /f/ differ in place, manner, and voicing). Contrasting two unknown, maximally opposed sounds is known as Treatment of the Empty Set (see a description here).

Multiple Oppositions: For kids with moderate-severe, consistent phonological errors and a collapse to one phoneme

• The rundown: Contrasts the known sound with 2–4 unknown sounds (e.g. tie vs. hi, pie, and try ). Intervention includes familiarization, imitation, independent production in play/drill-play, and conversation.
• Therapy intensity: High frequency (3 sessions/week) with 50+ trials per session for 10 weeks to maximize outcomes.
• The research: Supported by at least 19 studies (1 RCT). See our previous reviews here and here for more details and resources. 

For more details and a comparison of minimal pairs, maximal oppositions, and multiple oppositions (AKA the contrastive approaches), see this tutorial. For all contrastive approaches, the SCIP app from Dr. A. Lynn Williams is an excellent resource for target selection and therapy. 

Treatment bonus! Bringing literacy into the mix

We know children with SSDs may be at additional risk for literacy disorders—see our reviews on the relationship between SSDs and literacy here, here, and here. For kids where you suspect (or have confirmed) a literacy disorder, you can consider incorporating metaphonology in your treatment plan. This can look like targeting children’s explicit awareness of sounds’ distinctive features—place, manner, and voicing—using kid-friendly language. Some metaphonological approaches you may be familiar with include Metaphon (described by the creators here, or see the ASHA Practice Portal for a summary) and LiPS, although the evidence base for these programs is pretty limited. 

Integrated Phonological Awareness Intervention takes things a step further by focusing on letter-sound knowledge and phonemic awareness. Rather than indirectly support literacy skills while you’re targeting speech, this approach embeds speech production practice in literacy activities, like syllable and rhyme awareness, segmenting, blending, and manipulating individual phonemes. We know of 9 studies (1 RCT) supporting IPAI for improving phonological awareness skills (many used the rules from the Cycles approach to select targets), although two studies (1 RCT), suggest that it may not be sufficient (at least not in realistic dosages) to correct speech sound errors. If you’re interested, check out these free phonological awareness resources from Dr. Gail Gillon, who led much of the research on IPAI. 

I have questions. 

Is your brain full? Has the word “approach” ceased to have any meaning? Approach… approach… aPPROach. Anyway. While these… intervention methods look nice and clear-cut on paper (like here, in our printable chart), there’s a lot of clinical judgment involved in carrying them out, so let’s chat about some lingering questions you may have: 

So, I pick an artic approach if I think it’s "just artic," and a phonological one otherwise? Yes?

Not necessarily. Let’s actually put “just artic” to bed, shall we? According to Farquharson, “this phrase makes the assumption that this type of communication disorder is less important and less complex than others” and may cause clinicians unintentionally to restrict their treatment options. She suggests SLPs “consider approaches such as minimal pairs, even if the child has a single sound error.” 

Do I actually need to commit to just one approach? Can’t I mix and match?

If you’re wearing your cool artic-phono bifocals (3D glasses? Is that a cooler image?), you’ll NEED to mix and match to some extent to support both of those needs. The critical piece, which has sometimes slipped through the cracks, is this: if the child has (or may have) phonological errors, we need to clean up their phonological rules, so we need to choose a treatment approach that can do this. At the same time, we can’t forget to support accurate placement of the articulators. You’ll be pulling therapy components and concepts (like principles of motor learning, elicitation strategies, etc.) from articulation approaches to support this need.

But what if you have a child with a severe phonological SSD and literacy disorder on your caseload. Do you use Cycles, Maximal Oppositions, or a metaphonological approach? Unfortunately, friends, there isn’t a “right” answer here. Trust your clinical experiences and judgment to choose what you think will work for this particular child. Then, use regular data collection and feedback from the child and their family to monitor the effectiveness of the therapy approach. Don’t throw in the towel if it’s “not working” right away. Where we have the evidence to support it, we included details above about how long it may take to see results for a given approach. For Integrated Phonological Awareness Intervention, research suggests it may take 17–20 hours to see results, as compared to more like 30–40 hours of therapy for Cycles. If the child is not feeling the therapy, like say intense drill or even drill play = zero motivation, you may need to readjust. The child is making no progress—like really, no progress—you may need to readjust. We know you know therapy is a delicate balance of keeping the child motivated and making progress. Have confidence in your clinical expertise to back up your decisions!

Also, know that we’ve laid out the approaches for you as researchers originally designed and studied them. That said, there are a variety of reasons your clinical judgment might lead you to modify an approach for a specific child. Session length and frequency is one factor in particular that may be constrained by forces beyond your control. Again, you use your clinical judgment to modify the approach, but rely even more heavily on data and client perspectives to determine whether it’s working.

Finally, this list is not exhaustive. We've included the most common/popular approaches, but there are others out there!

What about the kids on my caseload who won’t participate in these types of structured, drill and drill-play interventions?

There are other options! Naturalistic approaches are an evidence-based choice for young children with co-occurring speech and language disorders, such as autistic kids and those with Down syndrome or cleft lip/palate. These approaches capitalize on children’s interaction and engagement during play to facilitate speech production—and they’re more easily implemented by parents and caregivers than the other approaches we’ve talked about. You can start with naturalistic recasting during play, which is just what it sounds like—repeating the child’s utterance back to them (but without the errored sound/s) in natural play activities. And if you’re already doing Enhanced Milieu Teaching (EMT) or a similar approach including strategies like arranging the environment, following the child’s lead, modeling, and expanding productions, you can add a phonological emphasis (EMT+PE) to simultaneously support speech and language in naturally-occurring conversations during play. Our review of a study of children with cleft palate who participated in EMT+PE lays out the core strategies for you, or you can get more detail in this article.

Where can I go to learn more?

Check out the research and resources linked above under each approach and in our downloadable chart. You can also consider:

• Textbooks! They are your friends here. We consulted this 2021 textbook edited by Williams, McLeod & McCauley heavily when putting together this piece, but we also love this one from McLeod & Baker. This one from Bernthal, Bankson, & Flipsen is another good option.
• ASHA’s Practice Portal for Articulation and Phonology
• This cool interactive resource for clinical decision-making from Ulster University in the UK
• Check out episodes 34 and 36 of the SeeHearSpeak podcast where guest host Dr. Kelly Farquharson (who consulted on this review), talks complexity and treatment approaches. 
  
   

Selected references

Allen, M. M. (2013). Intervention efficacy and intensity for children with speech sound disorder. Journal of Speech, Language, and Hearing Research. https://doi.org/10.1044/1092-4388(2012/11-0076) [available to ASHA members]

Almost, D., & Rosenbaum, P. (1998). Effectiveness of speech intervention for phonological disorders: A randomized controlled trial. Developmental Medicine & Child Neurology. https://doi.org/10.1111/j.1469-8749.1998.tb15383.x [open access]

American Speech-Language Hearing Association. Speech sound disorders-Articulation and phonology. ASHA Practice Portal. https://www.asha.org/practice-portal/clinical-topics/articulation-and-phonology

American Speech-Language Hearing Association. Selected Phonological Processes (Patterns)*. ASHA Practice Portal. https://www.asha.org/practice-portal/clinical-topics/articulation-and-phonology/selected-phonological-processes/

Bernthal, J., Bankson, N., & Flipsen, P. (2017). Articulation and phonological disorders: Speech sound disorders in children (8th ed.). Pearson. 

Brumbaugh, K. M., & Smit, A. B. (2013). Treating children ages 3–6 who have speech sound disorder: A survey. Language, Speech, and Hearing Services in Schools. https://doi.org/10.1044/0161-1461(2013/12-0029) [available to ASHA members]

Cabbage, K. L., & DeVeney, S. L. (2020). Treatment approach considerations for children with speech sound disorders in school-based settings. Topics in Language Disorders. https://doi.org/10.1097/tld.0000000000000229

Cabbage, K., Farquharson, K., & DeVeney, S. (2022). Speech sound disorder treatment approaches used by school-based clinicians: An application of the experience sampling method. Language, Speech, and Hearing Services in Schools. https://doi.org/10.1044/2022_lshss-21-00167 [available to ASHA members]

Dean, E. C., Howell, J., Waters, D., & Reid, J. (1995). Metaphon: A metalinguistic approach to the treatment of phonological disorder in children. Clinical Linguistics & Phonetics. https://doi.org/10.3109/02699209508985318 

Denne, M., Langdown, N., Pring, T., & Roy, P. (2005). Treating children with expressive phonological disorders: does phonological awareness therapy work in the clinic? International Journal of Language & Communication Disorders. https://doi.org/10.1080/13682820500142582

Dodd, B. (2013). Differential diagnosis and treatment of children with speech disorder (2nd ed.). John Wiley & Sons.
 

Dodd, B., Crosbie, S., McIntosh, B., Holm, A., Harvey, C., Liddy, M., .Fontyne, K., Pinchin, B, & Rigby, H. (2009). The impact of selecting different contrasts in phonological therapy. International Journal of Speech-Language Pathology. https://doi.org/10.1080/14417040701732590 [open access]

Dodd, B., Holm, A., Crosbie, S., & McIntosh, B. (2006). A core vocabulary approach for management of inconsistent speech disorder. Advances in Speech Language Pathology. https://doi.org/10.1080/14417040600738177 

Fabiano-Smith, L. (2019). Standardized tests and the diagnosis of speech sound disorders. Perspectives of the ASHA Special Interest Groups. https://doi.org/10.1044/2018_PERS-SIG1-2018-0018 [open access]

Fey, M. E. (1992). Articulation and phonology: Inextricable constructs in speech pathology. Language, Speech, and Hearing Services in Schools. https://doi.org/10.1044/0161-1461.2303.225  [available to ASHA members]

Farquharson, K. (2019). It might not be “just artic”: The case for the single sound error. Perspectives of the ASHA Special Interest Groups. https://pubs.asha.org/doi/10.1044/2018_PERS-SIG1-2018-0019 [open access]

Hassink, J. M., & Wendt, O. (2010). Remediation of phonological disorders in preschool age children: Evidence for the cycles approach. EBP Briefs. [open access]
 

Hesketh, A., Dima, E., & Nelson, V. (2007). Teaching phoneme awareness to preliterate children with speech disorder: a randomized controlled trial. International Journal of Language & Communication Disorders. https://doi.org/10.1080/13682820600940141

Kaiser, A. P., Scherer, N. J., Frey, J. R., & Roberts, M. Y. (2017). The effects of enhanced milieu teaching with phonological emphasis on the speech and language skills of young children with cleft palate: A pilot study. American Journal of Speech-Language Pathology. https://doi.org/10.1044/2016_AJSLP-16-0008
[available to ASHA members]

Maas, E., Robin, D. A., Hula, S. N. A., Freedman, S. E., Wulf, G., Ballard, K. J., & Schmidt, R. A. (2008). Principles of motor learning in treatment of motor speech disorders. American Journal of Speech-Language Pathology. https://doi.org/10.1044/1058-0360(2008/025)[available to ASHA members]
 

McLeod, S., & Baker, E. (2017). Children's speech: An evidence-based approach to assessment and intervention. Pearson.

McLeod, S., Verdon, S., Baker, E., Ball, M. J., Ballard, E., David, A. B., Bernhardt, B. M., Bérubé, D., Blumenthal, M., Bowen, C., Brosseau-Lapré, F., Bunta, F., Crowe, K., Cruz-Ferreira, M., Davis, B., Fox-Boyer, A., Gildersleeve-Neumann, C., Grech, H., Goldstein, B., Hesketh, A., Hopf, S., Kim, M., Kunnari, S., MacLeod, A., McCormack, J., Másdóttir, P., Mason, G., Masso, S., Neumann, S., Ozbič, M., Pascoe, M., Pham, G., Román, R., Rose, Y., Rvachew, S., Savinainen-Makkonen, T., Topbaş, S., Scherer, N., Speake, J., Stemberger, J. P., Ueda, I., Washington, K. N., Westby. C., Williams, A. L., Wren, Y., Zajdó, K., & Zharkova, N. (2017). Tutorial: Speech assessment for multilingual children who do not speak the same language (s) as the speech-language pathologist. American Journal of Speech-Language Pathology. https://doi.org/10.1044/2017_AJSLP-15-0161 [open access]

Miccio, A. W., & Elbert, M. (1996). Enhancing stimulability: A treatment program. Journal of Communication Disorders. https://doi.org/10.1016/0021-9924(96)00016-0 

Pennington, B. F. (2006). From single to multiple deficit models of developmental disorders. Cognition. https://doi.org/10.1016/j.cognition.2006.04.008

Ruscello, D. M., Cartwright, L. R., Haines, K. B., & Shuster, L. I. (1993). The use of different service delivery models for children with phonological disorders. Journal of Communication Disorders. https://doi.org/10.1016/0021-9924(93)90008-X

Rvachew, S., & Nowak, M. (2001). The effect of target-selection strategy on phonological learning. Journal of Speech, Language, and Hearing Research. https://doi.org/10.1044/1092-4388(2001/050)
[available to ASHA members]
 

Secord, W. A., Boyce, S. E., Donohue, J. S., Fox, R. A., & Shine, R. E. (2007). Eliciting sounds: Techniques and strategies for clinicians. Cengage Learning. 

Scottish Intercollegiate Guidelines Network. SIGN Grading System 1999-2012. https://www.sign.ac.uk/assets/sign_grading_system_1999_2012.pdf

Storkel, H. L. (2018). The complexity approach to phonological treatment: How to select treatment targets. Language, Speech, and Hearing Services in Schools. https://doi.org/10.1044/2017_LSHSS-17-0082 [open access] 

Storkel, H. L. (2022). Minimal, maximal, or multiple: Which contrastive intervention approach to use with children with speech sound disorders? Language, Speech, and Hearing Services in Schools. http://doi.org/10.1044/2021_lshss-21-00105  [open access] 

Van Riper, C. (1939). Speech correction: Principles and methods. Prentice-Hall. 

Williams, A. L., McLeod, S., McCauley, R. J. (2021). Interventions for speech sound disorders in children (2nd ed.). Paul H. Brookes.