Sentence:  Not only in formal discourse, but in the ordinary walks of life, a well-modulated, expressive voice is a most valuable asset, whether one's object be to interest, persuade or convince, to give a command or entreat a favor. The moulding of the voice into finished articulate speech is a mechanism in which the entire oral cavity, including palate, teeth, tongue and lips, take an important part. As a result of either structural defect of these organs, or, as is more often the case, as a consequence of their imperfect innervation, various logopathies may occur, which profoundly affect the social status of the unfortunate individual and seriously embarrass his way to a successful career./ Lisping, stuttering, stammering, lallation, <WSD>nunnation</WSD>, and sigmatism, paragammacism and paralambdacism are but few of the locutory evils encountered, much too frequently in adolescents and adults. The fact that they are mostly amenable to treatment and may often be completely corrected, with proper attention and training, is something that needs to be more thoroughly impressed upon our educational bodies and sociologic reformers. 
Meaning of the word marked with <WSD> tags:  A stammering speech disorder, in which the /n/ sound is given to other consonants.