Correlation Between Defective Articulation and Nasality in Cleft Palate Speech

Abstract

The basic purpose was to obtain evidence useful for answering the question of whether there is a tendency for degree of nasality to vary with defectiveness of articulation in the speech of children with cleft palate. Results of previous researcher (3) are quite contradictory, with Pearson rs for measuring the relationship varying from very small values with no evidence of any relationship between these two aspects of speech of persons with cleft palate to fairly large values which are highly significant. The Pearson r for estimating the relationship between two particular variables may, of course, differ considerably from one experiment to another depending upon the selection of subjects, especially when the range of the variables, in this case nasality and defective articulation, differs from one experiment to another. Nevertheless, in view of the very wide range of previously reported rs, with reference to an answer for the question under consideration, additional evidence appears to be needed. That incompetence of velopharyngeal closure is causally related to defective articulation in the speech of individuals with cleft palate appears to be a reasonable assumption, and evidence to support such an assumption has been reported (4). Another widely accepted and reasonable assumption is that incompetence of velopharyngeal closure is causally related to nasality in the speech of these same individuals (4). The relationship between degree of incompetence and degree of nasal— ity, however, according to recent research evidence (I), cannot be assumed to be necessarily close, although, at the same time, such an assumption would appear to be the most reasonable one; a more ade— quate measure of incompetence of velopharyngeal closure might be expected to provide the means for obtaining evidence to support a conclusion that degree of nasality in the speech of persons with cleft palate is highly dependent upon degree of incompetence of velopharyn-geal closure.