Lexical Properties of Stimuli in Standardized Articulation and Phonology Tests: A Short Report

The purpose of the present study was to report the phonological neighborhood density, phonotactic probability, and word frequency of the stimuli in 12 commonly used articulation and/or phonological tests. We extend the work of Macrae (2017), who identified variability in stimulus items across consonant singletons, consonant clusters, vowels, phoneme complexity, and bound morpheme. This study sought to augment that work with a deeper analysis of lexical and sublexical features of these stimuli.

The stimuli from 12 articulation and/or phonological tests were extracted, resulting in 667 stimuli. All stimuli were run through a phonological neighborhood density and phonotactic probability calculator. Word frequency was determined using Moe et al.'s (1982) database.

Means and ranges for all lexical characteristics were computed across each of the 12 tests. Most stimuli were from sparse phonological neighborhoods, and included common sound sequences. Although the average word frequency value was in the high range, overall, very few test stimuli were high-frequency words.

There was not one articulation and/or phonological test that considered or balanced these three lexical properties. We discuss the linguistic constraints surrounding developing such a test. We also discuss future research opportunities to examine if these lexical properties may result in over- and underidentification of children with speech sound disorders.