Discourse typifies Sheridan's simplistic interpretation and the evangelistic ardor with which he addressed his audiences. He was not content to fault an overemphasis in the study of Latin, nor was he satisfied to argue that "the support of our establishments, both ecclesiastical and civil" rests upon public discussion. Many in his audiences would have agreed, and few would have taken issue with the contention that the "art of elocution" needed further cultivation. But Sheridan pressed on to insist that the written language, being an invention of man, "can have no natural power," and he argued that the "highest delights" of aesthetic pleasures must wait upon the perfection of spoken English. He even went so far as to suggest that the study of "grammar, rhetorick, and oratory" explained the outstanding artistic achievements of Greece and Rome.

Moreover, "other benefits to society" would add to "the glory of the nation" and to the "ornament of individuals, and of the state in general" through a loosing of silent tongues. Sheridan dreamed that the study of elocution, with a voice "far sweeter than the syren's song," would so entrance young students that they would linger long in native academic groves, avoiding the baneful influence of travel abroad "at the most unfit and dangerous season of life." Thus, individual and social perfection had to be predicated upon the study of spoken English, and Sheridan implied that to slight this study was to offer an affront to the divine plan for earthly progress.

This panacean outlook prompted Hume to remark that "Mr. Sheridan's Lectures are vastly too enthusiastic. He is to do every thing by Oratory."[6] And it is not surprising that the critical, the Johnsons and Humes, should have been distressed by Sheridan's enthusiasm, an enthusiasm that permitted him to posit such unlikely goals and to see himself as the sole authority on elocution. Yet, for every negative reaction, the elocutionists enlisted countless believers. Sheridan and other theorists capitalized upon a number of intellectual currents and social pressures of the era that centered attention upon delivery in speaking and that helped aggrandize this facet of rhetorical training. A number of forces can be isolated, but most relate to the classical inheritance, to the belief that tones, looks, and gestures constitute a natural language of the passions, and to the methodology of science.[7]

The classical inheritance was important to the elocutionists because of the impetus given to all language study. Sheridan did no more than echo a common complaint when he worried over the "many bad consequences" attending a neglect of the English language; countless writers addressed themselves to a determination of phonology and pronunciation in the attempt "to methodize" the language. Furthermore, the example of ancient oratory spoke loudly to a people striving to perfect both the individual and social institutions. Any educated man was expected to be able to express himself well in public, particularly if his vocation found him "in the pulpit, the senate-house, or at the bar." The pulpit was a favorite target, and critics regularly lamented the atrocious state of speaking "in the very service of the Most High." The elocutionists and others appear to have been convinced that the doubt and scepticism of the age would be much relieved if only the preachers would learn to speak properly. Theirs seemed the best of all possible religions, and it needed but a vitalization through adequate pulpit oratory to transcend anything accomplished by the Popish devotees on the Continent. Certainly Sheridan's references to the Continent also reflect a strong overlay of nationalism, and the same spirit creeps into his worship of Greece and Rome; but he and the other elocutionists knew that they owed a profound debt to classical rhetorical theory. Beyond supporting language study generally and beyond encouraging an interest in public speaking, ancient rhetoric justified a concentration on delivery.

After centuries of a chameleon-like existence, the complete Ciceronian rhetoric emerged in England just in time to meet a savage onslaught from the methods of science and the new epistemology.[8] Eventually, rhetoricians such as Campbell and Blair were to successfully blend the old and the new, but the elocutionists found fertile ground in delivery alone. They began, as Sheridan did, with the testimony of Cicero and Quintilian because actio, or pronuntiatio, was one of the five established canons of classical rhetoric. A favorite citation, though Sheridan did not use it, was Demosthenes' reputed response when asked to name the three most important parts of rhetoric: "Actio, actio, actio." The endorsement of antiquity lent powerful support to the study of delivery, and this was the one canon that had not been subjected to regular exhaustive analyses throughout the rhetorical tradition. Here was a topic ripe for further investigation, and by Sheridan's day, the tones, looks, and gestures of delivery had achieved commonplace status in discussions of man's emotions.

Sheridan spoke as if this natural language of the passions were "hardly ever thought of," but the belief that tones, looks, and gestures were external signs of internal emotions was firmly established by the middle of the eighteenth century. The notion has received some attention throughout western thought, but most speculation appears to date from Descartes' Les Passions de l'ame in 1650. The increasing concern with mind-body problems encouraged inquiries into the nature and function of the natural language in all areas relating directly to man's emotion and its expression. The topics were as various as religion and physiognomy, but discussions of the natural language construct centered upon human communication, particularly in the arts.

The construct became especially significant in analyses of painting and sculpture. Examples of its impress can be seen in Le Brun's sketches of the passions,[9] in Hogarth's having embraced "the commonly received opinion, that the face is the index of the mind,"[10] and in Dryden's contention that "to express the passions which are seated in the heart, by outward signs, is one great precept of the painters." Dryden added that "in poetry, the same passions and motions of the mind are to be expressed,"[11] and the natural language found its way into most discussions of tragedy and the epic. Other examples of literary analysis in which the construct operated include Steele's Prosodia Rationalis, Say's An Essay on Harmony, Variety, and Power of Numbers, and Kames' Elements of Criticism. In sum, it was almost universally accepted that the creative artist was to observe and record the natural language of the passions. In Sheridan's words, he was to perceive and delineate the "operations, affections, and energies, of the mind itself ...