[If] children are required to utter correct sounds forcibly at the age when the organs of speech are most tractable, the habit of uttering words distinctively, and of pronouncing them correctly, will soon be formed. The voice should be early and frequently exercised upon the elementary sounds of the language … and classes of words containing sounds liable to perversion or suppression should be forcibly and accurately pronounced … If the learner habitually mispronounce words, if he pervert or suppress important sounds,—as prudunt for prudent, or boundin for bounding,—his attention should be directed to the table of words containing sounds similar to those mispronounced, and the voice should be exercised upon it until the defect is remedied.
Swan, William D. 1844. The Grammar School Reader, Consisting of Selections in Prose and Poetry, with Exercises in Articulation, Designed to Follow the Primary School Reader, Part Third, Improved Edition. Philadelphia: Thomas Cowperthwait and Co. pp. 3–5. || WorldCat