Speech Errors in the Production of Initial Consonant Clusters: The Roles of Frequency and Sonority

Purpose: One of the central questions in speech production research is to what degree certain structures have an inherent difficulty and to what degree repeated encounter and practice make them easier to process. The goal of this article was to determine the extent to which frequency and sonority distance of consonant clusters predict production difficulties. Method: We used a tongue twister paradigm to elicit speech errors on syllable-initial German consonant clusters and investigated the relative influences of cluster frequency and sonority distance between the consonants of a cluster on production accuracy. Native speakers of German produced pairs of monosyllabic pseudowords beginning with consonant clusters at a high speech rate. Results: Error rates decreased with increasing frequency of the consonant clusters. A high sonority distance, on the other hand, did not facilitate a cluster's production, but speech errors led to optimized sonority structure for a subgroup of clusters. In addition, the combination of consonant clusters in a stimulus pair has a great impact on production accuracy. Conclusion: These results suggest that both frequency of use and sonority distance codetermine production ease, as well as syntagmatic competition between adjacent sound sequences.
Speech production is a highly efficient and automatized process. In everyday communication, speakers produce an average of four to six syllables per second (Reetz & Jongman, 2009), and speech errors, [...]