It is well-known that early intervention is critical for children with phonological disorders. Everyday interactions present communication challenges. Furthermore, research suggests that children who arrive in kindergarten with unintelligible speech are significantly more likely to experience academic difficulties (Williams, 2005).

In the past, conventional wisdom has suggested that treatment should mimic typical development in that sounds are presented in developmental sequence. However, children with phonological disorders require different input because of their limited sound repertoires. Instead, a paradigm shift has occurred during the past fifteen years, demonstrating the efficacy of teaching phonetically-complex, later-developing and nonstimulable sounds.

Such a paradigm shift requires SLPs to carefully study and apply these principles. This effort leads to reduced treatment time and a more expedient return to classroom instruction. This page provides resources regarding the most critical concepts of complexity theory. Furthermore, SLPs have the opportunity to put the principles into practice for case studies (children ages 4-7) listed on this page. Pretreatment data is provided for these students. SLPs can utilize the Phonological Assessment and Treatment Targets (PATT) analysis form to identify targets that will lead to system-wide changes.

The resources on this page were provided at the two day conference on October 26th and 27th, 2010 in Lakewood, CA. All resources are copyrighted to Barlow, Storkel and Taps unless otherwise noted. We hope that you find the resources valuable in your practice.



This document summarizes implicational language laws identified in linguistic research. SLPs can utilize these implicational relationships to target complex sound classes and sound structures, which leads to significant gains in a child's phonological repertoire.


This document summarizes key research findings and how to put these principles into practice.


Adult learners benefit from creating a plan when applying new knowledge (Hanen, 2002). This resource allows SLPs to develop a plan to implement principles of complexity into their daily practice over time.


These documents feature a step-by-step sequence that allows SLPs to fully describe and analyze each child's phonological system in both English and Spanish.


This resource includes play-based activities that yield maximum practice in natural contexts during treatment.


Adam Wheewall (2003) created this helpful guide for understanding the International Phonetics Alphabet and various diacritics. It is reprinted with permission and can be freely distributed for noncommercial purposes.


Two Phonemic Inventory Worksheets are now available. One is organized by rows and the other by columns. Each includes room for SLP to record the child's production by vowels. These documents provide a structure for identifying minimal pairs. This should greatly facilitate the task of identifying the child's phonemic inventory. Please remember that a large sample is necessary for identifying both phonetic and phonemic inventories. This allows us to identify ideal target sounds. A document that includes tips for identifying phonemic inventory is also available for download.


Several years ago, San Diego Unified School District collected case studies from students within the district that illustrate the dramatic changes that unfold within sound systems when complex sounds are taught. These students were served by eight different SLPs and all added new sounds and structures (e.g., three-element clusters) to their sound repertoires. Interested parties can view each child’s pretreatment data individually or as a whole document.


SLPs can work through these case studies with the Phonological Assessment and Treatment Targets (PATT) analysis form and Phonemic Inventory Worksheet as practice for later application. This process allows SLPs to identify the sounds in the child’s phonetic and phonemic inventories and treatment targets that yield maximum change in the repertoire. Posttreatment data for each child is presented at each SLPath conference to demonstrate the system-wide changes that occurred as a result of targeting complex sounds.