A study reported in the Quarterly Journal of Speech (November, 1935) showed the existence of a phonetic factor of difficulty affecting the occurrence of stuttering spasms. Further analysis of the data on which the previous work was based has revealed a grammatical factor of difficulty. This is more consistent, but does not seem to be as important as the phonetic factor.
Proceedings of the Iowa Academy of Science
©1937 Iowa Academy of Science, Inc.
Brown, Spencer F.
"Quantitative Measurement of Some Psychological and Phonetic Factors Affecting the Incidence of Stuttering,"
Proceedings of the Iowa Academy of Science, 44(1), 158-159.
Available at: https://scholarworks.uni.edu/pias/vol44/iss1/70