The 18th century saw considerable effort on the part of the intelligentsia both in Europe and America to understand the natural world around them. Among the things being explored were how different types of diseases and disabilities would best be categorized. This included diseases underlying to speech disorders.

Other social movements during this century also affected the treatment of people with speech disorders. The egalitarianism arising from the spirit behind the French and American revolutions gave rise to a need for the creation of equal opportunities for the poor, for women, and for the non-enfranchised, including those with speech and language problems. There was an effort to standardize language and to promote the standard forms as a way for everyone to communicate.

As part of the investigation of the natural order of things that came with the enlightenment were studies of how speech and language was structured. Investigations were done of all aspects of the language system, including phonetics, prosody, the lexicon (the creation of dictionaries), morphology, and grammar.

The 18th century brought with a new sense of morality toward fellow human being. This led to a less physically abusive treatment of criminals, the poor, and those with intellectual challenges. In some cases, this moral treatment was replaced by another form of abuse, one that was psychological in nature.

Finally, there was a move toward egalitarian and universal education that would take hold in the next century in the form of the common school movement. Speech and educational therapies for the disabled were developed by people like Jean Itard, and tended to be empiricist and sensation-based learning theories of Condillac and Locke.

Among the memorable figures who had considerable impact on the next century’s developments affecting the communicatively impaired in America were Benjamin Franklin, Caleb Bingham, John Thelwall, and Jean Marc Itard.