First Advisor

Mary Gordon-Brannan

Date of Publication


Document Type


Degree Name

Master of Science (M.S.) in Speech Communication


Speech Communication




Intelligibility of speech, Articulation disorders in children



Physical Description

1 online resource (3, iv, 43 p.)


Previous research has indicated that speech and linguistic variables develop concurrently. When one aspect of speech and linguistic development is delayed, there are typically associated delays in another area as well. This interactive relationship has been studied extensively in the context of phonological and syntactical development, as well as fluency and syntactical development. The relationship between intelligibility and linguistic proficiency has not been studied as extensively. The purpose of this study was to examine the relationship between varying levels of intelligibility and length and complexity of language in preschool-aged children. Mean length of utterance was correlated with the mean percentage of intelligible words in a continuous speech sample. The following questions were addressed: 1. Does a significant positive correlation exist between MLU and percentage of intelligible words in a continuous speech sample? 2. Are there significant differences in the correlations of MLU and percentage of intelligible words between four groups of young children with a range of intelligibility levels: mild, mild-moderate, moderate-severe, and severe? A continuous speech sample was collected from each of the subjects. Children were separated into four groups based on intelligibility ratings of mild, mild-moderate, moderate-severe, and severe. These ratings were based on the percentage of mean intelligible words in a continuous speech sample. Correlations between mean length of utterance (MLU) and the percentage of intelligible words (PIW) were obtained using the Pearson Product Moment Correlation. Regression analysis was used to determine whether a significant difference exists between the correlations for the four groups of intelligibility. An overall significant positive correlation was found between MLU and PIW when the four groups of subjects were combined. Significant correlations were also found between MLU and PIW for the groups with intelligibility ratings of mild and mild-moderate. No significant correlations were revealed between the two variables for the moderate-severe or severe groups. Regression analysis indicated no significant differences in the correlations for the four groups of intelligibility. This resulted in a failure to reject the null hypothesis that the correlations among the four groups of intelligibility levels will be the same.


In Copyright. URI: This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).


If you are the rightful copyright holder of this dissertation or thesis and wish to have it removed from the Open Access Collection, please submit a request to and include clear identification of the work, preferably with URL

Persistent Identifier