Date on Master's Thesis/Doctoral Dissertation


Document Type

Doctoral Dissertation

Degree Name

Ph. D.


Psychological and Brain Sciences

Degree Program

Experimental Psychology, PhD

Committee Chair

Mervis, Carolyn

Committee Co-Chair (if applicable)

Pani, John R.

Committee Member

Pani, John R.

Committee Member

Cashon, Cara H.

Committee Member

Smith, Alan

Committee Member

Velleman, Shelley

Author's Keywords

articulation; Williams syndrome; 7q11.23 duplication syndrome; phonological; articulatory pattern


Williams syndrome (WS) and 7q11.23 duplication syndrome (Dup7) are associated with communication disorders (Huffman et al., 2013). However, articulatory accuracy has not been systematically examined in these populations. The dissertation involved two studies. Using standardized citation assessment, Study 1 addressed articulatory accuracy with regard to age norms and differences between groups. Results indicated that for both groups, (a) consonant accuracy was significantly below expectations, (b) older children pronounced consonants with significantly better accuracy than younger children, (c) children with IQs at or above 70 earned significantly higher articulation standard scores, and (d) for particular groups of consonant sounds, arranged as a function of features of articulation, significant differences were found across consonant groups for (c.1) expected period of acquisition in development, (c.2) articulatory place of production, (c.3) articulatory manner of production, and (c.4) movement transition across consonants within clusters. Study 2 addressed variance relations among speech articulatory accuracy, phonological processing, and particular cognitive and linguistic measures. Articulatory accuracy was shown moderately, to strongly, related to each study variable. For the children with WS, articulatory accuracy contributed unique variance to phonological processing beyond that contributed by verbal short-term memory, spatial ability, and the combined factor of lexical understanding and use. Overall, the results showed children in both groups were significant delayed in consonantal development. Patterns of articulatory accuracy did not differ greatly from those of younger, typically developing children. Furthermore, the findings demonstrated positive relations among articulatory accuracy, phonological processing, intellectual abilities, and vocabulary abilities for children with these syndromes.