The Phonemic Inventory Probe (PIP) was constructed to further assess a child’s phonemic inventory. It targets contrasts between /p/, /t/, /k/, /w/, /l/ and /r/ so that SLPs can determine whether or not these six sounds are in a child’s phonemic inventory. This page includes the long version of the probe, a short version, transcription forms, a manual with suggested prompts, and a guide that explains for the rationale for this task.
The two documents below provide an example of how to utilize the PIP to select a three-element cluster for treatment. As Gierut and Champion (2001) suggested, a child must have the second and third consonant of a three-element cluster in his/her phonemic inventory in order to teach the cluster. For example, if /spr-/ is targeted, the child already needs to have /p/ and /r/ in his/her phonemic inventory.
Stoel-Gammon (1986) stipulated that there must be two occurrences of a sound functioning as a phoneme for inclusion in the phonemic inventory. Contrasts can occur in any word position - initial, medial or final. A child may produce [wak] and [lak], demonstrating a contrast for /w/ and /l/ in initial position. He/she may also produce [hip] and [hit], demonstrating a contrast for /p/ and /t/ in final position. Please note that a contrast may also occur between a consonant and no consonant. For instance, a child may produce [bo] and [bot], demonstrating a contrast between no consonant and /t/ in final position.
The first document features the results from Ella, age 3;11, on this task. The second document features the analysis of this data. As you can see, Ella's phonemic inventory subset included /p t k w/ (but not /l r/). Therefore, /skw-/ is a viable treatment target. /str-/, /spr-/, /skr-/ and /spl-/ are not viable targets because she is missing the third consonant (/l r/) in each of these clusters.